I agree, the reasons are dumb, but it's going to be wiped. What if they change the story missions? Change some crucial things for the beginning of the game? What if some of the game isn't final and we have something that's not in the final game? Gotta take that into consideration too. Nothing in the Beta is final and is subject to change. It'd be stupid to carry stuff over in entirety. The most I'd suspect would transfer over to the full game is anything left in your vault or whatever you have in your inventory. I would rather not have characters carry over.