well, that's if you aren't cooldown maintaining your way through the AQ stuff... and eventually later content like guild order (mobs easily have 1mil+ hp there).
debuffs that come back before the next enemy wave is still better since mobs with high HP naturally will eat up a chunk of turns
it's nice if you can get some milage out of it, but i gotta agree that hypnos barely gives much with that skill, if at all