Why does Esuna have a Cast Time?

[NobleWinter]

I wonder why Esuna has a freaking 2.5s recast time.

I would love if the cast and recast time were the same but it does let you weave a lustrate or Tetragrammaton in afterward which is nice sometimes. I still think Esuna should be a trait tied to the tiny heals like Cure, Physick, etc. That way you get a tiny heal and a random debuff removed for the cast time involved.