The big question is still “will they succeed?” Two issues are key here. First, the movies are protected by a DRM solution that limits significantly the ways you can use the movies you just bought. Second, and maybe more important, the price issue will play a significant role: about the same price as the physical DVD in a plastic box and with a booklet (9.99$ to 26.00$) but with only the download.
I am not sure this is the best way to push the sales up. The market will tell.