So, I guess this is the DVD/BRD equivalent of AutoRip, which Amazon has been providing for audio CDs? That sounds like it could be a good feature, were it not for the malicious DRM that will inevitably be required to play these digital copies. Also, given Amazon's track record, I'm sure these digital copies will be deleted without warning long after the testing is done, in a strangely George Orwell-like manner.
Personally, I'd stick with an old-fashioned DVD. After all, a DVD can't be deleted remotely, so there's no risk of Amazon basically stealing the thing you paid for. If you want to play the DVD on a mobile device, you could easily rip it and re-compress it (assuming that doing so is legal where you live).