Guys, I also have a software background, oddly enough. One of the lessons I've learned so far in 30-odd years doing this professionally is that there are pitfalls to making judgments about what is "simple" to implement when you don't have knowledge of the inner workings of a particular product. I'm not going to get into those inner workings, but I hope that you'll accept my assurance that what you're suggesting, while certainly possible, is not simple.
In the meantime, by the way, if you go into the Movie Store section in the Strato UI, if you scroll up a couple of rows you'll find "My Movies". That view shows everything you've purchased. Movies that you've downloaded can be played directly from there. Movies you don't own can be downloaded. It's definitely not everything you're asking for -- there's no way to filter the view to just show the movies that aren't downloaded, for example. But it is a way to find an owned movie in the OSD to find a movie and download it without having to go to the web or the app if you don't have either of those handy. If you're looking for a specific movie you can of course also search.