Look I love to complain about this game's lack of direction as much as the rest of you, but I have to give credit where credit is due.
Phoenix Down in regular casual content is very worthwhile. It's a pain when you're at a midboss in an Expert roulette and suddenly the healer goes splat. The tank might be able to survive the content on their own, but reviving the healer brings everybody back on their feet and substantially reduces the amount of time in the roulette.
I'm not a SMN/RDM main and I'll be happy to bring the healer back to life it means avoiding 25 minutes of the tank solo'ing the boss and wasting people's time.