I know the purpose is to remove buffs from enemies.
The application is simple: carry those weapons with you, equip them only to hit the enemy ONCE to remove their buffs, then continue with another weapon.
So my question now: Is Funcom expecting me to carry extra buff sets with me all the time? But as soon as the enemy notices I rebuffed, they simply hit me once again with their cleansing/Plundering weapon and poof, buffs gone. You are better off doing builds without buffs.
The thing is, there is no counterplay except being a dodge god. A possible addition here could be anti debuff buffs, which when used, will give you cleansing/plundering protection for the next 10 hits or so.
Those weapons are btw all banned on most private PvP servers.