I would think a PVD coating would have to be VERY VERY cheap to "wear off." In fact, I've never seen PVD coating wear off on any watch. I've seen poor coatings chip and scratch if handled roughly, but wearing off doesn't sound like something that could even happen with PVD. It's not a plating like gold plate, and the coating process has nothing in common with plating.
As for the Grahams, I have a V2 ChronoDiver and the PVD coating on it is incredibly durable. Mine has not a single chip or scratch in the coating, and I even bought the watch used. I go far as to say it's a non-issue.