10 Video Game Items That Are Completely Useless (On Purpose!)
In theory, all of Griftah's wears are greatly useful. They do things like protect you from Tikbalangs, make food and drink heal you, and let you swim through water.
Only, these are all things you already have. You automatically gain the ability to swim in-game, food and drink already heals you, and Tikbalangs don't exist in the game - so it's safe to say that you're pretty safe from them.
On the plus side, though, his items are expensive enough that only more advanced players would be able to afford them, and these players are well aware of the extent of their abilities, and of Griftah's scams.
In fact, this even led to an in-game event surrounding the sketchy salesman, where he was exiled from Shattrath City temporarily because of his shady shop.
When players complained about their favourite conman going away, Blizzard informed them that this wasn't them removing Griftah from the game, but rather creating a storyline for him in order to try and create a more engaging and immersive world.
They did also mention that people had been tricked into buying his wares, though, which is pretty impressive given how transparently useless they all are (except for the pets you can buy as a rogue, which are very cute).