This sounds like one of the dumbest things on the planet. If they called them Wall Mart coins you'd be freaking out and talking about the destruction of money. Amazon wants to "mint their own currency" and it will just be pegged to the dollar. It's little difference between that and a giftcard in my personal opinion. I get the impression that if you put a dollar in you shouldn't be expecting a dollar in value in return, Amazon has to make their money somewhere. Profits don't exist in a vacuum, when you put dollars into Amazon they want to do everything in their power not to give you as many dollars in return, bit coin has a chance, this won't even get off the ground.
So, in order to buy from Amazon, they're going to add another screen where you first have to pay dollars for Amacoins, and then back to your transaction where you pay for your goods? That's not going to be very helpful. Otherwise, why on earth would anyone want to tie up any of their liquid assets into Amazon until the moment they need them to pay for stuff? Or is this going to be another way to fuck over people who sell privately on Amazon, who will now not get paid ever?