What is the point of having potions available if you can't use them?
In that quote of Zanzi you listed, I believe he was referring to the idea that it's looked down upon when potions are used
during the fight. In reality, you're not going to be albe to drink down something all the while you're getting attacked. (Unless you're just a godly fighter compared to them, kinda like being an experienced verteran of three wars, dancing around swings from a lowly rat, all the while, you're playing the fiddle. )
But for the most part, using potions while during the middle of a fight, is generaly frowned upon. That isn't to say that you shouldn't be able to drink a few
after the fight. But there again, gulping down 20 potions in a moments notice, well, even to call something "magic", there are still limits.
I could be wrong though, I guess you'd have to wait for him to clarify himself.