I see it more situational.

For tanks pop a vitality before a big hit. Healers top you, stoneskin, adlo..and you are ready. I think that mega potion of vitality on a correctly geared tank is around 1000HP boost.

If all dps pop a (str, dex, int, mnd if healer ) potion during a phase that needs a quick dps that might do the trick.
Not impressive if only one person uses it, but surely noticeable if all do at the same time

But they should separate cooldowns. I don't see which role would not be needed if they separate cooldowns