I personally think this is a good thing. I think Google does a great job of getting utility out of their UX, and while this doesn't really do more than the utility of streaming music for the realm of competitors that it is venturing up against I think the more "non-google" it looks, the better. (Disclaimer: I have not used the android music marketplace, which I think might be closest to this area of design for Google of stuff they already had live).
I think that's precisely what parent comment is referencing; the Music design scheme may be familiar to Android users, but non-Android users likely see it as a bit surprising/inconsistent. Two quick examples: button styling and top account-bar background.
This is also somewhat revealing of how Google wants this app perceived. I see it as leaning _heavily_ toward a native experience on Android devices, and a push from that mobile experience into the browser. It's interesting.
