I understand their optimizations, that said, many people listen to music while driving and will have spotty connections, even commuting to/from the burbs. So it's a negative experience that probably outweighs the bandwidth issues. Even a couple songs in buffer at 64kbps encode in the background is better than letting it freeze multiple times a minute for 10+ seconds at a time.

They're too aggressive on their optimizations for mobile networks/devices.