It kills me that Google, owner of Youtube, would not directly integrate Youtube and Google Music. I can only assume this is once again a limitation imposed by the RIAA. Sigh.
Of all the bone headed product decisions made at Google, the fact that Android owns Google Music makes me say "WHY?????"
Its not an RIAA limit (and somehow, you all extend much more power to the RIAA than they have in these matters). It's a Google endemic product org issue.
as someone else said they did announce youtube integration through artists hub as well as linking to purchasing the track from youtube. http://music.google.com/artists/ - at the bottom is screenshot of what it will be like.
What else would you do?
EDIT: Actually, the answer is kind of obvious now that I've pondered it a little bit. We can only hope that a deeper integration is in the pipeline.