actually it is dl and keep under certain circumstances (w/ limitations set to protect). and it certainly will be more so in the near future. so that is not a valid argument.
First of all, I'm not trying to win an argument. Some, though not all, of us will want the physical disc at least for some of our movies. My DVD collection won't fit on 6TB of hard disc space, so I gave up on that idea quite a while back. Many of them are transfers from VHS to DVD. They never made it to DVD. I suspect many movies on DVD will never be offered on-line. I don't mind walking over to the shelf and selecting a DVD. No sense in making it more complicated than it needs to be. Music, however, is a different story.