I think this is a good move on Sony's part. Nobody will buy a $25,000 tv set with no 4K content available to showcase the worth of the TV.
It will be interesting to see how Sony handles the server they are loaning to the end consumer and how often they update it and whether the upconverted movies look meaningful in 4K or not.
It will also be interesting to see how many units Sony actually moves in the next quarter or two.. It will determine if the R&D was worth it for Sony or not as well as whether they will make any price reductions in the TV itself.