What i don't understand is why they haven't implemented a "buy song" or at least "tip the artist" a-la flattr. I don't think it would degrade the experience and would remove the hassle of setting up a separate bandcamp/whatever page.
They have that. You can fill in any url as the "buy link" and it gets linked as "buy this track" or whatever, at the bottom of the player, next to the download link.
Seems like kind of a stopgap, I imagine it was something users really wanted and this was a way to do it with almost no engineering effort. Maybe an actual retail section is part of their plans...
