I think it's the future all UWP, but its not for me yet.
Two main things hold me back
1) Fruity loops the full version hasn't been centennial'd yet.
2) Games. Game developers and users have a bit of convincing to come over. If I were MSFT, I'd try and cut a deal with steam.
As for windows s, I'd always like to option to sideload appx files (uwp's). So I'd never be an s user. For various reasons sometimes apps don't make it to the store. Store guidelines and such. If I used android, or chromeOS or macOSX, it'd be the same - I'll happily use the store, I'd love the fast and sandboxed app platform, but I don't like to be tied down.
However, such a system would be great for people that are technophobic, schools and libraries and people with minimal software needs.