Pact Weapon Proficiency

[Nagog]

Question for the Playground: Is a Pact of the Blade Warlock proficient with all weapons? AS in, they are proficient with all weapons that they create/bond with their Pact, so if I had a BladeLock that has a bound weapon of say, a lance, and my party found a +1 lance or something, would my Bladelock be proficient with it? If no, would binding to it grant proficiency with it? The wording of the Pact of the Blade says you're proficient with any weapon you create, then explains that you can bind any weapon to you as your pact weapon, but does not state that doing so grants proficiency in it.

[Protolisk]

The Pact boon means they are proficient with the pact weapon, but not all weapons. So you aren't proficient with lances, but you are proficient with your pact weapon, which coincidentally is a lance. But other lances aren't your pact weapon, so you aren't proficient.

To clarify, the key phrase is "You can use your action to create a pact weapon in your empty hand. You can choose the form that this melee weapon takes each time you create it. You are proficient with it while you wield it."

You are only proficient with "it", and if you stop wielding "it", you lose proficiency. The "it" is the pact weapon, not the class of weapons.

[Nagog]

The Pact boon means they are proficient with the pact weapon, but not all weapons. So you aren't proficient with lances, but you are proficient with your pact weapon, which coincidentally is a lance. But other lances aren't your pact weapon, so you aren't proficient.

To clarify, the key phrase is "You can use your action to create a pact weapon in your empty hand. You can choose the form that this melee weapon takes each time you create it. You are proficient with it while you wield it."

You are only proficient with "it", and if you stop wielding "it", you lose proficiency. The "it" is the pact weapon, not the class of weapons.

But if I bond to a lance, am I proficient with it? To put the question into linguistic terms, does the "It" that is the subject of the first sentence regarding proficiency refer to "Pact weapons you create" or is it just "Pact Weapons", including any magic weapon I turn into my pact weapon?

[Protolisk]

"You can transform one Magic Weapon into your pact weapon by performing a Special ritual while you hold the weapon."

Once you bind to it, it is now your pact weapon. Previously stated, you are proficient with your pact weapon.

[Millstone85]

Once you bind to it, it is now your pact weapon. Previously stated, you are proficient with your pact weapon.That would make sense, so of course Jeremy Crawford disagrees.

link (https://twitter.com/JeremyECrawford/status/834853685368856576)

You're quoting text that refers to a weapon the warlock creates, not a magic weapon that the warlock transforms.

[Protolisk]

That would make sense, so of course Jeremy Crawford disagrees.

link (https://twitter.com/JeremyECrawford/status/834853685368856576)

Every time I read his explanations, I am more and more dumbfounded.

By his own admittance, it's DM based. I'd DM rule it that way, but I guess anyone can read it differently.

[Nagog]

But by RAW it's only created weapons. Ok, good to know. I always figured created weapons was a better option than a bound weapon anyway, particularly considering the Pact Weapon invocations and that drawing a weapon doesn't take an action like summoning one does. So owning/storing a magic weapon and having another one summon-able is probably the best bet.

[Daghoulish]

But by RAW it's only created weapons. Ok, good to know. I always figured created weapons was a better option than a bound weapon anyway, particularly considering the Pact Weapon invocations and that drawing a weapon doesn't take an action like summoning one does. So owning/storing a magic weapon and having another one summon-able is probably the best bet.

Not really. Thirsting blade only works when you attack with your pact weapon, as does lifedrinker. Meaning with that magical weapon that's not your pact weapon you only get 1 attack and no special affects. Even eldritch smite requires your pact weapon.

[Nagog]

Not really. Thirsting blade only works when you attack with your pact weapon, as does lifedrinker. Meaning with that magical weapon that's not your pact weapon you only get 1 attack and no special affects. Even eldritch smite requires your pact weapon.

But if I have a +3 summoned Maul, the weapon damage is 2d6+3, and I can use it as a spellcasting focus. On the other hand, I can have a bound +3 Greatclub and the damage is 1d8+3, and I can't cast while holding it without War Caster. Alternately, I could have a bound +3 short sword and the damage is 1d6+3 and I have one free hand for spellcasting, presumably with a focus. I can Eldritch Smite/Thirsting blade with any of them. Which would you rather have?

Personally I'd rather have the magic item not bound to me, as the only perk I get from having it bound is being able to summon it as an action so I can't be disarmed of it. But I can do the same with a created weapon, so unless the magic weapon has a unique ability and I absolutely cannot lose it ever and there is a chance it could get stolen, I don't think I'd ever bind a magic weapon over creating one myself.

[Daghoulish]

But if I have a +3 summoned Maul, the weapon damage is 2d6+3, and I can use it as a spellcasting focus. On the other hand, I can have a bound +3 Greatclub and the damage is 1d8+3, and I can't cast while holding it without War Caster. Alternately, I could have a bound +3 short sword and the damage is 1d6+3 and I have one free hand for spellcasting, presumably with a focus. I can Eldritch Smite/Thirsting blade with any of them. Which would you rather have?

Personally I'd rather have the magic item not bound to me, as the only perk I get from having it bound is being able to summon it as an action so I can't be disarmed of it. But I can do the same with a created weapon, so unless the magic weapon has a unique ability and I absolutely cannot lose it ever and there is a chance it could get stolen, I don't think I'd ever bind a magic weapon over creating one myself.

A pact weapon is not a spellcasting focus without improved pact weapon. Even then you can't summon a +3 maul, only a +1 with improved pact weapon. Again, if you have a magic weapon that is not your pact weapon you can't attack twice with it as it doesn't fulfill the requirements for thirsting blade. Later in your career it also doesn't qualify for lifedrinker, which adds your charisma in damage with every hit. I would rather that magic weapon go to one of my allies if I wasn't going to use it so it would see some use as it's actively bad for a blade pact warlock to not have their weapon as their bound weapon.

[JackPhoenix]

In addition to what Daghoulish said, you can cast spells with two-handed weapon just fine. Two-handed quality only matters when you're attacking with it. You don't need both hands just to hold it.

[RSP]

Bound magic weapons, RAW, receive all benefits of being a Pact Weapon once they are bound as a Pact Weapon. The key is:

“You can transform one magic weapon into your pact weapon by performing a special ritual while you hold the weapon.”

“Transform” is a strong word with a very specific meaning. For instance, if you were to say “a caterpillar transforms into a butterfly” you’re saying what used to be a green, long, many legged, non-winged insect, is now a butterfly, with all the traits that come with being a butterfly, regardless of what it was before the “transformation.”

Likewise, the “transformed” magic weapon becomes the Pact Weapon, with all qualities associated with being a Pact Weapon (Thirsting Blade, Lifedrinker, summoning/creating, proficiency, etc.)

[JakOfAllTirades]

That would make sense, so of course Jeremy Crawford disagrees.

link (https://twitter.com/JeremyECrawford/status/834853685368856576)

This sort of nonsense makes me very relieved that JC's tweets were downgraded from "official rulings" to "rules advice."

Which I ignore because he's flat out wrong.

[Nagog]

A pact weapon is not a spellcasting focus without improved pact weapon. Even then you can't summon a +3 maul, only a +1 with improved pact weapon. Again, if you have a magic weapon that is not your pact weapon you can't attack twice with it as it doesn't fulfill the requirements for thirsting blade. Later in your career it also doesn't qualify for lifedrinker, which adds your charisma in damage with every hit. I would rather that magic weapon go to one of my allies if I wasn't going to use it so it would see some use as it's actively bad for a blade pact warlock to not have their weapon as their bound weapon.

Improved Pact Weapon, Superior Pact Weapon, and Ultimate Pact Weapon. It's a growth tree that gets you up to a +3 weapon with Ultimate.
I understand that Thirsting Blade can't be used with weapons that aren't your pact weapon, my point is that a simple magic weapon, unless it has some kind of utility effect, will not compare to a martial weapon of the same magical caliber. As per J. Crawford (see quote linked below), you're only proficient with a Martial pact weapon if it's one you've created rather than bound.



Bound magic weapons, RAW, receive all benefits of being a Pact Weapon once they are bound as a Pact Weapon. The key is:

“You can transform one magic weapon into your pact weapon by performing a special ritual while you hold the weapon.”

“Transform” is a strong word with a very specific meaning. For instance, if you were to say “a caterpillar transforms into a butterfly” you’re saying what used to be a green, long, many legged, non-winged insect, is now a butterfly, with all the traits that come with being a butterfly, regardless of what it was before the “transformation.”

Likewise, the “transformed” magic weapon becomes the Pact Weapon, with all qualities associated with being a Pact Weapon (Thirsting Blade, Lifedrinker, summoning/creating, proficiency, etc.)
See below:

That would make sense, so of course Jeremy Crawford disagrees.

link (https://twitter.com/JeremyECrawford/status/834853685368856576)

[Millstone85]

As per J. Crawford (see quote linked below), you're only proficient with a Martial pact weapon if it's one you've created rather than bound.Note, however, that Crawford's tweets no longer count as official rulings. This is now reserved to the Sage Advice Compendium.

[Nagog]

Note, however, that Crawford's tweets no longer count as official rulings. This is now reserved to the Sage Advice Compendium.

Has there been a Sage Advice on the topic?

EDIT: There is:

https://www.sageadvice.eu/2017/04/01/does-a-warlock-need-proficient-in-pact-weapon/

[Daghoulish]

Improved Pact Weapon, Superior Pact Weapon, and Ultimate Pact Weapon.

Does not exist in 5e, there is only improved pact weapon.

[Millstone85]

Has there been a Sage Advice on the topic?Nope, there is just one on how you can not change the form of a bounded weapon.


EDIT: There isThis is not the Sage Advice Compendium.

The SAC is a file on WotC's site. Version 2.3 (https://media.wizards.com/2019/dnd/downloads/SA-Compendium.pdf) is the most recent.

[Nagog]

Does not exist in 5e, there is only improved pact weapon.

Except that they do exist, they're all from the same UA.

https://media.wizards.com/2017/dnd/downloads/20170213_wizrd_wrlck_uav2_i48nf.pdf

[Daghoulish]

Except that they do exist, they're all from the same UA.

https://media.wizards.com/2017/dnd/downloads/20170213_wizrd_wrlck_uav2_i48nf.pdf

Those are UA and unofficial content, while Improved pact weapon has come out in Xanathars guide. Most DM's that I know do not use UA, and for good reason. UA involves things that are not balanced, such as the lore wizard.

[Nagog]

This is not the Sage Advice Compendium.

This isn't in the document, but it's from the forum that they get the questions from to make the Compendium. So 2/3 official sources (All written by the same folks) say you don't get proficiency with a bound weapon unless you're already proficient, and the third source is silent on the matter. Obviously this means the 2 sources have been overturned.

[Nagog]

Those are UA and unofficial content, while Improved pact weapon has come out in Xanathars guide. Most DM's that I know do not use UA, and for good reason. UA involves things that are not balanced, such as the lore wizard.

Cool. But my tables do use UA, so... Yeah. Even if you don't want to factor something like that into your calculations because of your tables' choice on what material to use, a +3 greatclub is 1d8+3, averaging 7.5 damage, while a +1 maul is 2d6+1, averaging 8 damage. Summoned maul wins out in sheer damage, to say nothing of the utility of summoning any weapon of any type you may need and using it as a spellcasting focus.

[Protolisk]

Improved Pact Weapon, Superior Pact Weapon, and Ultimate Pact Weapon.

See here:

Besides Improved Pact Weapon, those additional invocations were UA that never made it into Xanathar while improved Pact Weapon did. They are not official.

I would further stop listening to Jeremy Crawford reading of this rule, even though he is a major writer of the system, simply because the use of a magic weapon that does not give you proficiency would be pathetic. You "must" use the weapon without your proficiency bonus, so it doesn't matter if it's a +3 weapon, because it'd be at a 3+CHA/STR. Any other weapon you make would be 1+CHA/STR+6(prof bonus at level 17), increasing your to-hit chance by 20%. If we DID include up to Ultimate Pact weapon, then it's CHA/STR+6+3, a 30% increase. It seems mind boggling that you would do this ritual to a weapon but not gain proficiency as you could literally make a better one.

The damage bonus of a plus 3 weapon over a plus 1 that you made is almost inconsequential (just +2) when you miss out 1/5th the time. The damage you gained was lost under the to-hit chances.

[JackPhoenix]

This isn't in the document, but it's from the forum that they get the questions from to make the Compendium. So 2/3 official sources (All written by the same folks) say you don't get proficiency with a bound weapon unless you're already proficient, and the third source is silent on the matter. Obviously this means the 2 sources have been overturned.

Don't know why is that in blue. SA is *not* official source, it's 3rd party site that puts tweets in one place. Those tweets are also not official sources. Only SAC has any claim to be called "official".

[Protolisk]

As an aside, I'll use this thread as another reason for why Hexblade's Hex Warrior should have been given to Pact of the Blade, instead of an adiditonal bonus for just the subclass. Giving flat martial weapon proficiency would have solved all these issues.

[Nagog]

Besides Improved Pact Weapon, those additional invocations were UA that never made it into Xanathar while improved Pact Weapon did. They are not official.

I would further stop listening to Jeremy Crawford reading of this rule, even though he is a major writer of the system, simply because the use of a magic weapon that does not give you proficiency would be pathetic. You "must" use the weapon without your proficiency bonus, so it doesn't matter if it's a +3 weapon, because it'd be at a 3+CHA/STR. Any other weapon you make would be 1+CHA/STR+6(prof bonus at level 17), increasing your to-hit chance by 20%. If we DID include up to Ultimate Pact weapon, then it's CHA/STR+6+3, a 30% increase. It seems mind boggling that you would do this ritual to a weapon but not gain proficiency as you could literally make a better one.

The damage bonus of a plus 3 weapon over a plus 1 that you made is almost inconsequential (just +2) when you miss out 1/5th the time. The damage you gained was lost under the to-hit chances.

Allow me to rephrase what you just said, to be sure I understand correctly:

We should not listen to Jeremy Crawford, who writes much of the Sage Advice that is considered RAW, because:
1. He has not made this claim in the currently supported method of amending RAW, only in ways that were previously accepted
and
2. It doesn't make sense.

Also more damage is negligible because you might miss.

I got that correctly, right? Ok just making sure. Here we go:

Jeremy Crawford is, as previously stated, one of if not the most socially active of the Sage Advice writers. Sage Advice is considered RAW since it was published, before that his tweets were considered RAW, and he stated that then as well as on the Sage Advice forum. Just because he has not stated it a 3rd time and had it published does not negate the previous 2 times it was posted, it simply means there are less people asking about it.

As for the proficiency, I think it makes more sense that the weapon you created out of the magic you spent your soul to attain is much easier to wield than the same shape made of enchanted steel that you can summon.

There are plenty more ways to increase your odds of hitting a target, many of them spells you can cast through your summoned weapon that you'd have to produce/store your spellcasting focus to cast if you have a bound magic weapon.

[Daghoulish]

link (https://twitter.com/JeremyECrawford/status/834853685368856576)

So, I'm going to go full conspiracy theorist right now. This tweet was posted on Feb-2017. Interestingly I checked the date of when Xanathars came out and the hexblade was made official, Nov-2017. Hmm, almost makes one wonder if Jeremy intentionally made the blade pact weaker to promote the fact that Hexblade was coming out and trying to sell more books. But he wouldn't do that right?

[Nagog]

So, I'm going to go full conspiracy theorist right now. This tweet was posted on Feb-2017. Interestingly I checked the date of when Xanathars came out and the hexblade was made official, Nov-2017. Hmm, almost makes one wonder if Jeremy intentionally made the blade pact weaker to promote the fact that Hexblade was coming out and trying to sell more books. But he wouldn't do that right?

In the same vein, the UA that first unveiled the prospect of the Hexblade (And Raven Queen and the Superior/Ultimate Pact Weapon invocations) also came out in February 2017. Perhaps the initial decision was made to make the proficiencies granted by Hexblade that much more distinct from the base class?

Jeremy we've talked about this, nerfing someone does not buff everybody else

[Protolisk]

Jeremy Crawford is, as previously stated, one of if not the most socially active of the Sage Advice writers. Sage Advice is considered RAW since it was published, before that his tweets were considered RAW, and he stated that then as well as on the Sage Advice forum. Just because he has not stated it a 3rd time and had it published does not negate the previous 2 times it was posted, it simply means there are less people asking about it.


Here are more reasons why I wouldn't listen to this version.

This was a Sage Advice Compendium from 2016. In it, it DOES reserve the right for Jeremy Crawford to make official rulings in his tweets.
https://media.wizards.com/2016/downloads/dnd/SA-Compendium.pdf

However, THIS is he Sage Advice Compendium from 2019.

https://media.wizards.com/2019/dnd/downloads/SA-Compendium.pdf

Note that this specific mention of his tweets has now been updated to read that tweets can be a preview to what will make it into Sage Advice Compendium, and often does. But no longer does it say that the actual Sage Advice tweets are actually official, just the Sage Advice Compendium itself.

That tweet was in 2017. If it was really relevant, it would have made its way in.

However, no where in EITHER of these compendiums does his ruling about magic weapons that underwent the ritual explicitly does NOT get the proficiency, but it DOES mention that you can't alter the shape of magic weapons into other shapes.

And on that topic, both versions have this to say:

The warlock’s Pact of the Blade feature (PH, 107–8) lets you create a melee weapon out of nothing. Whenever you do so, you determine the weapon’s form, choosing from the melee weapon options in the Weapons table in the Player’s Handbook (p. 149). For example, you can create a greataxe, and then use the feature again to create a javelin, which causes the greataxe to disappear.

You can also use Pact of the Blade to bond with a magic weapon, turning it into your pact weapon. This magic weapon doesn’t have to be a melee weapon, so you could use the feature on a +1 longbow, for instance. Once the bond is formed, the magic weapon appears whenever you call your pact weapon to you, and the intent is that you can’t change the magic weapon’s form when it appears. For example, if you bond with a flame tongue (longsword) and send the weapon to the feature’s extradimensional space, the weapon comes back as a longsword when you summon it. You don’t get to turn it into a club. Similarly, if you bond with a dagger of venom, you can’t summon it as a maul; it’s always a dagger.

The feature initially allows the conjuring forth of a melee weapon, yet we allow more versatility when it comes to magic weapons. We didn’t want a narrow focus in this feature to make a warlock unhappy when a variety of magic weapons appear in a campaign. Does this versatility extend outside the melee theme of the feature? It sure does, but we’re willing to occasionally bend a design concept if doing so is likely to increase a player’s happiness.

Emphasis mine.

I suppose that could be read as it only pertains to using the shunting ability. If that was the case, then why specifically mention that it is your pact weapon? And why are you proficient with your pact weapon in normal Pact of the Blade use? Especially when they "didn’t want a narrow focus in this feature to make a warlock unhappy when a variety of magic weapons appear in a campaign".

It feels so wrong to read these rules that you aren't proficient in your pact weapon when you are proficient in your pact weapons. The previous sentence is intentionally confusing, and that style of reading the rules is not in the Sage Advice Compendium. To which I conclude:

You are proficient in your pact weapon.

[JackPhoenix]

We should not listen to Jeremy Crawford, who writes much of the Sage Advice that is considered RAW

At no point, ever, was SA considered RAW. Not even SAC is considered RAW. RAI? Sometimes. RAW? Never.

[Nagog]

Here are more reasons why I wouldn't listen to this version.

This was a Sage Advice Compendium from 2016. In it, it DOES reserve the right for Jeremy Crawford to make official rulings in his tweets.
https://media.wizards.com/2016/downloads/dnd/SA-Compendium.pdf

However, THIS is he Sage Advice Compendium from 2019.

https://media.wizards.com/2019/dnd/downloads/SA-Compendium.pdf

Note that this specific mention of his tweets has now been updated to read that tweets can be a preview to what will make it into Sage Advice Compendium, and often does. But no longer does it say that the actual Sage Advice tweets are actually official, just the Sage Advice Compendium itself.

That tweet was in 2017. If it was really relevant, it would have made its way in.

However, no where in EITHER of these compendiums does his ruling about magic weapons that underwent the ritual explicitly does NOT get the proficiency, but it DOES mention that you can't alter the shape of magic weapons into other shapes.

And on that topic, both versions have this to say:

The warlock’s Pact of the Blade feature (PH, 107–8) lets you create a melee weapon out of nothing. Whenever you do so, you determine the weapon’s form, choosing from the melee weapon options in the Weapons table in the Player’s Handbook (p. 149). For example, you can create a greataxe, and then use the feature again to create a javelin, which causes the greataxe to disappear.

You can also use Pact of the Blade to bond with a magic weapon, turning it into your pact weapon. This magic weapon doesn’t have to be a melee weapon, so you could use the feature on a +1 longbow, for instance. Once the bond is formed, the magic weapon appears whenever you call your pact weapon to you, and the intent is that you can’t change the magic weapon’s form when it appears. For example, if you bond with a flame tongue (longsword) and send the weapon to the feature’s extradimensional space, the weapon comes back as a longsword when you summon it. You don’t get to turn it into a club. Similarly, if you bond with a dagger of venom, you can’t summon it as a maul; it’s always a dagger.

The feature initially allows the conjuring forth of a melee weapon, yet we allow more versatility when it comes to magic weapons. We didn’t want a narrow focus in this feature to make a warlock unhappy when a variety of magic weapons appear in a campaign. Does this versatility extend outside the melee theme of the feature? It sure does, but we’re willing to occasionally bend a design concept if doing so is likely to increase a player’s happiness.

Emphasis mine.

I suppose that could be read as it only pertains to using the shunting ability. If that was the case, then why specifically mention that it is your pact weapon? And why are you proficient with your pact weapon in normal Pact of the Blade use? Especially when they "didn’t want a narrow focus in this feature to make a warlock unhappy when a variety of magic weapons appear in a campaign".

It feels so wrong to read these rules that you aren't proficient in your pact weapon when you are proficient in your pact weapons. The previous sentence is intentionally confusing, and that style of reading the rules is not in the Sage Advice Compendium. To which I conclude:

You are proficient in your pact weapon.

Except there is no change to the way Pact of the Blade is listed. The part about proficiency in the Pact of the Blade description is two paragraphs ahead of the bit about binding a magic weapon, and the subject of that paragraph is Summoned Weapons, not Bound Weapons. If it never mattered either way, why does Hexblade get Martial Weapon Proficiency as a class feature?
Your argument still boils down to "It hasn't been stated recently and not in a forum I recognize as RAW, therefore it's not true." when there is plenty of evidence to the contrary, both stated by J. Crawford and with context given the surrounding material (Hexblade getting martial weap prof, warlocks in general not getting Martial Weap Prof, the fact that the proficiency comment is stated referring to summoned weaps rather than bound, etc.).

As for the reference to the SA, you're basing the argument on the fact that they use the term Pact Weapon, but in the same passage they acknowledge a difference between Summoned and Bound pact weapons, as you cannot change the shape of a Bound weapon. They then state the reason for this to be not having Warlocks miss out on magic item distribution, but this does not say that they are proficient with any magic weapon they come across when they bind to it. This would imply that Rangers would similarly miss out on magic item distribution because they aren't proficient with heavy armor, when in fact, there are plenty of magic armors that are not heavy. Similarly, there are plenty of magic weapons that are not martial weapons. However, a Warlock having to choose between a +1 summonable martial weapon against a Flame Tongue Shortsword they have to lug around, they'd go with the Flame Tongue, and their Pact would become useless. that is what they're explaining.

[RSP]

Except there is no change to the way Pact of the Blade is listed. The part about proficiency in the Pact of the Blade description is two paragraphs ahead of the bit about binding a magic weapon, and the subject of that paragraph is Summoned Weapons, not Bound Weapons. If it never mattered either way, why does Hexblade get Martial Weapon Proficiency as a class feature?
Your argument still boils down to "It hasn't been stated recently and not in a forum I recognize as RAW, therefore it's not true." when there is plenty of evidence to the contrary, both stated by J. Crawford and with context given the surrounding material (Hexblade getting martial weap prof, warlocks in general not getting Martial Weap Prof, the fact that the proficiency comment is stated referring to summoned weaps rather than bound, etc.).

I’m not sure I understand what you’re trying to argue. The RAW is clear, and it’s similarly clear what JC thinks, if That’s what you want to go with instead of RAW.

Hexblades getting Martial Weapon Proficiency is so they can dual wield (another fix from how Pact of the Blade was originally designed).



As for the reference to the SA, you're basing the argument on the fact that they use the term Pact Weapon, but in the same passage they acknowledge a difference between Summoned and Bound pact weapons, as you cannot change the shape of a Bound weapon. They then state the reason for this to be not having Warlocks miss out on magic item distribution, but this does not say that they are proficient with any magic weapon they come across when they bind to it. This would imply that Rangers would similarly miss out on magic item distribution because they aren't proficient with heavy armor, when in fact, there are plenty of magic armors that are not heavy. Similarly, there are plenty of magic weapons that are not martial weapons. However, a Warlock having to choose between a +1 summonable martial weapon against a Flame Tongue Shortsword they have to lug around, they'd go with the Flame Tongue, and their Pact would become useless. that is what they're explaining.

I’m not sure I agree with your assessment of RAI here, but again, you’re breakdown of the RAW is not correct: the RAW is the bound magic weapon gets the abilities stated for Pact Weapon.

[Zalabim]

That would make sense, so of course Jeremy Crawford disagrees.

link (https://twitter.com/JeremyECrawford/status/834853685368856576)
I've explained this nuance before, and I may be incorrect about it, but I have the impression the questioner was asking if making a longsword +1 your pact weapon requires the warlock to have proficiency with longswords, or if making the longsword +1 your pact weapon gives proficiency with longswords. The answer is neither.

"does a Warlock need prof. in a magic weapon to convert it to pact weapon, or does it[proficiency] become innate?" Someone else (with a name like Snark Confidant) then tries to "gotcha" with "RAW states "You are proficient with it while you wield it." Therefore, it grants proficiency if you don't already have it." (underline added) Crawford is trying to explain that it does not grant proficiency. He never comes right out and says you may not be proficient when you attack with your pact weapon, and there's never any official answer added to the sage advice compendium, I presume because it's a confusing distinction to make that is unlikely to ever come up because using a longsword that is not your pact weapon'd longsword +1 is so rarely considered since it wouldn't qualify for any of the other invocations that require the pact weapon.

Anyway, Hexblades have martial weapon proficiency because they might not have pact of the blade and Hex Warrior requires you to be proficient with the weapon you choose.