Disney Movies Anywhere is what UltraViolet should have been; buy a movie once, and watch it on nearly any device — without needing to download a separate app or video player. It already works across Android and iOS (plus popular digital retailers like Vudu), and today Disney is adding Amazon Video, Microsoft Movies, and TV to the mix. Next week, a Disney Movies Anywhere app will launch for Roku's set-top boxes and Android TV.

Why can't UltraViolet be this convenient?

So pretty soon it'll be incredibly simple to watch your Disney, Pixar, Marvel, and Star Wars films regardless of which device is in your hands or in your living room. Once you've linked your Disney account, all of those movies will appear right inside Amazon Video and also Microsoft's video apps for Windows and Xbox. (There are stand-alone Disney Movies Anywhere apps available for Xbox and Amazon's Fire devices if you prefer to watch that way.) The expansion coincides with today's release of Avengers: Age of Ultron, which is hitting digital services long before it reaches Blu-ray on October 2nd.

The "buy once, watch anywhere" promise is a huge draw for parents looking to keep a vault of Disney's classics for their kids, but it also removes any stress that typically comes with choosing where to buy a movie digitally. Your movies go with you across nearly any major platform, and while UltraViolet shares the same strategy, Disney has pulled it off in a way that's remarkably seamless. It's also probably the only studio with enough pull and influence to make this happen.