But it's the screen the matters, is it not? Who cares if you get scratches and scuffs on the backplate. I'm sure you could just buy a replacement if you really wanted to. It's the screen that matters.
Baby steps. Gorilla Glass hasn't had this issue so bad from what I hear. And the backing will only work with light scratches, so cracking the back is still going to set you to SCREWED. Not to mention there are materialists who will love this feature.
The healing feature is probably the rupture of plastic monomer and catalyst nano capsules. The monomer and catalyst flow and mix in the scratch creating new plastic. I wouldn't scratch the same area to many as the ability to repair will diminish quickly.