http://www.howtogeek.com/243012/why-...windows-store/
Windows 10 Store apps use an entirely different container app (i.e. the executable) than games from more classic digital distribution platforms. because of that, games on the platform are strictly inferior:
1. NO Dual GPU support like SLI or Crossfire.
2. NO disabling of Vsync, which can lead to input lag and worse performance.
3. NO dedicated fullscreen, only borderless Windows, which again screws with performance.
4. NO Modding. So no mods, no SweetFX and no 3rd party improvements.
5. NO Exe, so you can't add it to Steam as a non-steam game, and thus no Steam controller support.
6. NO Overlays. You can't do a steam overlay, you can't have a Fraps FPS counter, you can't have Overwolf. This ALSO means that you can't use Fraps or OBS to record the game window. You can still record the full monitor, but not the window itself.
7. NO mouse macros.
8. NO easy way to refund the game. For refunds, you have to chat with a representative, so you're not even sure you could get it refunded.
9. NO cross-platform purchasing. If you decide to rollback to Windows 7 or 8, you won't be able to take your store games with you. Same for Linux, SteamOS and OS X.
10. NO store-based support for the game. If you want to have support for your game, you'll have to go through the Steam forums. There is no easy way for developers to provide support through the Windows store.
All of the above are objective flaws: Each of these is a feature that's present in the Steam version, but not in the Windows 10 version.
All of this will probably prove to be problematic when Quantum Break releases, because Microsoft has already announced plans to only release Quantum Break on PC through the Windows 10 Store.