Call me old fashioned but...
I think it's a great idea. My cars have stereos with SD slots in them, and I like the idea of being able to buy albums on SD, keep them in the car and play them just by slotting it in the SD slot.
I'm one of those old fashioned types that actually likes to own thier music. If I hear something l like, I will buy the CD. This is because (and I'm sure it's an age thing) I am very proud of my large CD collection. It's a talking point when visitors come 'round. "Ooh haven't you got a big one" etc...
Trouble is, I'm also lazy... So, copying various CDs to SD so I can listen to them in the car is a pain in the arse... If I could go and buy an album on SD for a tenner, that would be great; chuck it the car and leave it there.
I hope the first one they release is Brothers in Arms ;-)
(Giving my age away)