You may know that Microsoft just added a music locker function to OneDrive. If you have a Windows or Xbox device you can upload your own music to the cloud and have access to it from within the Xbox Music app or the Xbox Music web player.
If you're an Xbox Music subscriber there's a little bonus as well: 100GB of extra storage.
As far as I can tell visiting the Music folder from within the OneDrive app is all that it takes to activate the extra storage and it appears to be a worldwide offer too - not always guaranteed with some of Microsoft's promotions.
Given that you have access to all the music you could want through your Xbox Music subscription there doesn't seem to be much point in uploading your own catalogue, but it could be useful for integrating tracks that aren't currently available from the streaming service.
Otherwise it appears that you can just go and enjoy all that extra free storage for any document you like.