I'm surprised that nobody thinks this is a good idea. To the poster above that said it's like a car with helicopter blades, I have a better analogy: This is like a car with two motors. One motor is street legal and can be driven in all fifty states. The second is a fully modified fire-breathing 800HP monster that can only be used in closed-course racing. When you're driving to work you use the street legal motor, but you can drive the same car to the race track and get the full potential of the second motor.
As MP3 players get more and more storage space, we're going to see scenarios similar to those in desktop computers - Grandma only needs a fraction of that 500GB drive in her new eMachine. The same will be said for Sally the high school student with her 60GB iPod. If that space is available why not fill it with the highest quality music possible so that music is available wherever one goes? I understand that it won't be playable in my iPod but it will be available to hook up to a stereo or computer etc etc at a friends house / party / barbecue.
Am I alone? :-)