It has a fast decay exactly because of PvP, if you’re going to raid a clan, tactic and planning should be involved, each player should have a role, once you start a raid, having no cooldown on potions, it becomes too easy to abuse builds, for exemple;
Lets say in this scenario, Im alone defending my base, and two guys come in, one is specced for pvp, and the other for encumbrance to carry the bombs.
Only one can really fight me as the other would die easly risking losing the bombs. With no cooldown, or a very long one, they could bring respec potions, store the bombs and the one that was encumbrance becomes pvp, then they kill me, one of then back to encumbrance, finish the raid, and won, no chance for the solo to defend.
Scenario 2, im alone, solo player, raiding an offline clan, im specced for encumbrance, manage to get into the base after several bombs, even destroyed their potion station in the process, and when I was about to destroy one vault, I could see they log in by the player list, quickly, I grab my potion in my bag, respecc for pvp, kill them, destroy their beds, finish destroying the vault, respec again for encumbrance (because I had more than one potion on my bag) and run with all the stuff.
Potions must have a short cooldown, otherwise, it becomes too easly to do everything in one go.