Why are Vitality potions still a thing?

[Kyuuen]

I can't for the life of me figure out the use. You get a few seconds extra HP WITHOUT HEALING UP THE ADJUSTMENT so it is useless in every bit of content right off the bat. If it healed you up the dif in HP, I could see it be somewhat useful for surviving a TB maybe but oh my gods, what a waste of resources of having a new 'better' version of something that will never be used each expansion.

And no, it being used as a healing item is no reasonable arguement for allowing it to exist the way it currently is. Have the potion do something else than (de)buff HP or remove it all together.

I'd say you're pretty on the money for it's uses. I could see an OT popping one with regen assistance in prep for an upcoming TB in order to save Invulns for emergency situations and making prog in new content. But outside of that; generally speaking, fairly useless.