> Practically, Reg E is essentially as strong as Reg Z.

Not even practically, but that's beside the point. The point is that with regulation E, I am potentially put in a position where I have to work to get my money back; I have to file a lawsuit against the bank if I think their determination is wrong (and that's assuming there isn't an arbitration provision, but many people don't realize they agreed to binding arbitration).

With regulation Z, the bank has to work to get their money back. They have to file the lawsuit against me if they really want the money. And it's $0 liability under many circumstances mandated through the regulation, not just a revocable promise from the bank.