Uses for Delayed Spell metamagic

[Elysiume]

Delayed Spell is an interesting metamagic that has a lot of restrictions:

Benefit: A delayed spell can be activated as a standard action anytime within 1 minute per spell level of being cast. Only spells that target one or more squares or grid intersections can be affected by Delayed Spell, and the target (as well as any other variables determined at the time of casting) cannot be changed once the delayed spell is cast. You can have as many delayed spells as you wish at any given time, but only one spell can be triggered in a single standard action. Though a delayed spell does not manifest until it is triggered, it emits a magical aura as normal and can be identified with Knowledge (arcana) as a spell effect in place. A delayed spell uses up a spell slot 1 level higher than the spell’s actual level.

It takes a standard action to activate so you don't save on action economy unless the spell you're delaying took longer than that to cast initially.
The spell must target a square or grid intersection.
The target must be selected when you initially cast the spell.
The only use I can think of would be something incredibly niche like pre-casting Forbiddance and being able to hold it back for a few minutes to potentially surprise people, e.g. if someone was coming into your lair you could pre-cast Forbiddance and drop it behind them once they're inside. Anyone have any interesting ideas?

[NotASpiderSwarm]

Delay a fireball on a crowded market square, wait for a certain person to walk past the casting point, blame them for the resulting carnage?

If it didn't require a Standard Action, it could be a niche way to take advantage of surprise or pull off a combo, but as-is, I can't see spending even a PF feat on it.

[MaxiDuRaritry]

Unless you can find a spell that affects a 2-D plane and not a 3-D one, I can't imagine this being particularly usable.

[Darg]

Setting a trap where you don't have to be in range or sight of the area.

Makes it harder to know that you cast the spell in question if no one sees the cast itself.

The description doesn't specify that you have to be the one to activate the spell. So cast some delayed spells and have your party activate them. Unless your enemy knows what or how to activate the spell it is unlikely they would. It's entirely vague on literally any activation requirements other than "requires a standard action."

Hmm, I don't think I'll be able to come up with other ideas.

[Bucky]

Use it to release an area Dispel Magic-type effect under an effect that would otherwise prevent you from casting entirely, in order to try to get rid of that effect.

Use it to release a harmful effect with minimum safe distance greater than its range after leaving the area.

[icefractal]

Man that's situational, even more than the 3e one.

Probably the best use is that if you have insane Stealth abilities and can cast silently, you could sneak up to a group of foes, plant a delayed spell amidst them, then go around a corner before setting it off. They jump to combat mode, look all around ... and see nothing. Wait until they calm down a little and then do it again. Fails if they're passively detecting magic though.

If it didn't raise the spell level, I could see some mildly useful tricks with illusions. Cast a fireball at the entrance of a room ahead of time, have a illusion of a wizard that you're controlling from around a corner pretend to cast it, and then set it off.

Or against intruders on your home terrain, set up some peepholes or other surveillance so you can trigger it without having LoS. But it probably only works once, because it's detectable as magic before being set off.

Not usually applicable to PCs, but you could use it for magical terrorism. Go cast something nasty in the town square, then be somewhere else establishing an alibi when you set it off.
(Edit: But not that far away! Just noticed it's a minute per spell level, so you don't really have that long.)

Now if it were something you could anchor on creatures instead of fixed locations in space, that would be a lot more useful. Put a powerful but short duration buff on someone, then activate it when they shout (or use Telepathic Bond), for example. Or stick a Fireball on a beetle and shoo it under a door that has enemies on that other side.