Download songs from playlist(s) (some or all from particular playlist) to device without syncing whole library. (my phone has very limited storage and my desktop collection is way to big). Let say you just made new playlist on your computer. You love it and wish to listen to it on your way. You don't have time to "play" with cables. You press one button on mmremote and songs are downloading to your device while you taking the shower.
I'm not sure if it's possible but it would be even better to sync files on device after modifying playlist on the computer (assuming that playlist name hasn't changed).