SanDisk's proposal of selling music on microSD cards reminds me of the failed attempt by Sony to sell pre-recorded MiniDiscs a decade ago. Before that was the Digital Compact Cassettes. Both failed miserably mainly because people knew they can just ripped their CD collection into cheap blanks. This was what I and countless of my mates did, and we still have our CD collection to convert into whatever is the newest greatest compressed digital format.
SanDisk's slotMusic idea may be great if they preload the cards with a lossless format like FLAC, but even then it will introduce a secondary step to convert the files for players without lossless support. But this is moot anyway, as SanDisk will be dumping lossy 320kbps MP3 files into those tiny cards instead. Unlike say, Blu-Ray, it does not provide any meaningful benefits over CD! If you willing to pay for lossy files, you may as well just save yourself a hell a lot of inconvenience and hassle by downloading them off a legal site anyway. And it really isn't that difficult to slot your CD into your PC and run an audio grabber program anyway!
Still I expect plenty of gullible people to buy into them. Those in the know will hold on to their 44.1 16-bit audio, thankyouverymuch.