With Windows 10 Microsoft will have a single unified store for purchasing apps, music, TV shows and movies. During the preview phase not all experiences of the apps where activated, in April Microsoft added TV and movies to the beta app and overnight music content has been added. The store now enables you to purchase songs and albums directly from the app, if you have an Xbox Music Pass subscription you can still add songs to your collection via the music app but for purchasing new songs you now use the new store apps.
So the store now has music, apps, movies and TV shows in one location which is probably a better user experience. Music is available in the US, Canada, Ireland, Australia, New Zealand and the UK.
In a post on the Windows Blog Microsoft say that the new music and video apps are the default experiences going forward and that the “Preview” music and videos apps will be removed in future builds.