So unmatched audio, will this still get "backed up" and also be able to be played by different devices through the cloud?

So unmatched audio, will this still get "backed up" and also be able to be played by different devices through the cloud?

I see that it might still get copied, howeer, its unclear if you can play it?

I have a lot of mp3s I didn't get on itunes and many are dj mixes, so they will NOT be on itunes.