Until we've got any measure of confidence that UV will be a reliable and dependable service, I don't see it as being particularly useful compared to my current setup (media centre with several drives, contents regularly synced to a tower elsewhere in the house to mitigate against disc failure, future plans to make backup copies onto offsite-stored backup-only drives as well). Why would I want to stream a film to my phone or netbook if I can encode a suitable copy from the media myself and circumvent the hassle and data charges?
I'd like it to evolve into something useful, but I fail to see how being able to stream the film I've just bought on physical media is of use to me, especially when there's no guarantee that the UV licences will be perpetual. Look at what book publishers are trying to do with libraries buying ebook lending licences (forced licence expiration periods based on what would happen, on average, if the ebook in question was a paper book!).