Stuff that cause sleep, fear, charm etc.
I've been ignoring them all game but I'm starting to wonder if they're actually Super useful
I'm way earlier than you are and I've found them all super useful, so yeah. For example, in the third Palace Oni is an annoying piece of shit since he has no weaknesses and is strong against physical attacks. So if he appears with other enemies, I target their weaknesses, then if I have no status attack on that Persona for the MC, I baton pass to Ann to put him to sleep. It works every time. Then after he misses his turn I score a technical attack on him with the next character.
Even better if you can use a Marin Karin or whatever on him, which doesn't wear off when attacked. You can basically take entire enemies out of play this way.