The main benefit of Windows 10 on Xbox is that it will enable developers to publish Universal Windows Apps & mobile games to the Windows app store on phone, PC and Xbox with only minor UI adjustments required. An example they demoed at the developer conference was the USA Today app made for Windows 10 which as you'd expect featured news articles on phone/PC but on Xbox was completely centered around the video content in the app instead. Theoretically you could publish a podcast app for Windows 10 PC, Xbox, & phone without having to change almost any of your code. This is very different from Mac OS, iOS and Apple TV where a developer has to rewrite an app for each one of those platforms. A Windows 10 developer can code once and publish their mobile game or app to Xbox/PC/phone. The other advantage that Windows 10 will bring are the development bridges that make it easy for developers to port apps and games from iOS and Android to Windows 10. What this means for consumers is more apps, faster updates, and in some cases the ability to buy an app/game once and own it on your Windows PC, Xbox, and phone. Cross buy will be up to the publisher to decide though.