It sounds like UltraViolet is nothing more than a unified standard for video on demand. In this case, multiple providers (e.g. Comcast to your TV, Verizon to your phone) all know about your purchase and can deliver your movie in a variety of formats. This is a win only if UltraViolet is accepted: not only by the movie studios (the typical challenge), but by all of the content providers as well.

Personally, I'd rather see the TV deprecated completely and handle all of my media through the Internet. If this has to happen via many different content providers, that's fine, and it may be better in terms of competition, but I'm not convinced it's all that necessary. It seems to me that the actual delivery of the video is nothing something that matters a whole lot to the average consumer, as long as they are getting their video now. Thus, it's more important to focus efforts on getting all of the content creators (movie and tv studios) to cooperate. Once you have the content, it's a simple matter to create different streams for different purposes and provide the movie on demand to any device. If all of the streams are essentially coming over the Internet, this is easy to do through one channel.