There's nothing special here (like uncompressed audio or hi-def audio would have been) that can't be easily downloaded and copied to portable flash memory already.
320kbps MP3 is uncompressed, as far as your ears can tell (http://en.wikipedia.org/wiki/ABX_test). Even if you transcode it (to a decent format), the audio is transparent (http://en.wikipedia.org/wiki/Transparency_(data_compression)).
High-definition audio is not nearly what it's cracked up to be. The only advantage of "HD" audio (24-bit/96kHz) compared to ordinary audio (16-bit/48kHz) is that HD audio can tolerate more post-processing without becoming distorted due to rounding errors. It turns out this doesn't actually matter if you have well-designed equipment, because you can get the same effect by upsampling an ordinary audio signal before doing any signal processing on it.
CDs aren't going anywhere. There are thousands upon thousands of people out there who aren't even remotely tech savvy and wouldn't know what to do with a microSD card if you plugged it into their player for them. And trust me, that market is way bigger than the very small group of people who would actually be stupid enough to buy compressed music on physical media instead of just downloading it, especially since most of the trends toward digital distribution models are growing in popularity merely because people are really, really, really fucking lazy and have absolutely no self control when it comes to making impulse purchases. And digital distribution takes full advantage of both of those facets.
Quoted for truth.