Concealed Spellcasting - Skill trick vs. skill use

[Kafana]

So I was under the impression that you can hide your spellcasting attempt only as a skill trick from CS. After reading about the additional skill use of sleight of hand in RoS, I'm not sure what the difference is. Why would I need the skill trick exactly?

[With a box]

buy some sticks from macket and pretend that is some kind of wand/staff (UMD)
I'd rather use silent spells to hide vocal component from party wizard listen it

[HammeredWharf]

I suppose RoS just isn't widely-used. I, for one, didn't know it improved SoH.

[Kafana]

Well, is this a RAW error then?

[Curmudgeon]

There's no error; the uses are a bit different. Consider a spellcaster surrounded by melee opponents. Using the Conceal Spellcasting trick, any of those enemies who don't beat the caster's Sleight of Hand check with their Spot will be deprived of spellcasting-provoked AoOs. On the other hand, using just a Sleight of Hand check could mean the spellcaster would deprive every one of those enemies of the chance to make a Spellcraft check to identify what spell was being cast — except every one of them would get to take an attack of opportunity (even if they didn't know the specific reason for why the enemy they surrounded let down their guard).

[Psyren]

Note that the Races of Stone sleight of hand use was actually reprinted in Rules Compendium 117. So it's even more legitimate now.

And yeah, there's no real reason to use the skill trick beyond a potential corner case like the one Curmudgeon describes. Since skill tricks cost resources and are only useable 1/encounter or 1/5 minutes, I would advise skipping the skill trick and using the skill use instead.

[Diarmuid]

Curm, that's not how I'm reading the RoS SoH expansion. It doesnt explicitly get into the mechanical benefit granted by beating the opponent's Spot, but it says that failure to do so results in in your casting not going "unnoticed". To me, this means that success would mean your casting would go unnoticed, right?

[Curmudgeon]

Curm, that's not how I'm reading the RoS SoH expansion. It doesnt explicitly get into the mechanical benefit granted by beating the opponent's Spot, but it says that failure to do so results in in your casting not going "unnoticed". To me, this means that success would mean your casting would go unnoticed, right?
Yes, the spellcasting would go unnoticed, meaning the verbal and somatic components wouldn't be heard or seen, and consequently there would be no opportunity to make any Spellcraft checks to identify the spell. However, not detecting the spellcasting isn't the same as the spellcasting not happening. Casting the spell is what makes the spellcaster let their guard down in combat, and that means all the enemies get to make AoOs.