The Guild has come out against this feature for fairly obvious reasons (hey! We're not getting a cut of the new way for people to enjoy our product.). As I predicted, this isn't going over great (blind people say, you jackasses -- what, you don't want us to read anything that isn't available in braille or on audio?) even tho the Guild is trying to say, no we just don't want the sighted people getting the bennies you blind folk do. And then there's the whole reading-to-the-kiddies aspect of the puzzle.
I _think_ this is really all about drive-time: people have long commutes. Books on whatever make those enjoyable. A kindle reading mechanically is hella less money than buying each book individually. And maybe a lot of those drivers don't give a flying leap about having Jim Dale read to them (not that the Potter books are available on the kindle, anyway).
I don't care too much how this turns out, really. It's just fun watching Roy Blount Jr. have to be conspicuously unpopular, a position I suspect is he not used to. He's not very good at it, either.