I have one of them mp3 capable mobile phones and I have a 4GB NAND flash inserted in it that is packed with music I like. Yet I never end up using it as a music player.
I see people everywhere use their phones for music and I repeatedly read and hear the soon coming death of the portable music player being predicted not far away by opinion-expressing know-it-allers.
My phone plays mp3 files just fine, but there are several reasons why I don’t use it for that. The primary one being that it gets a lousy battery run-time if I do that, and if I’d run down the battery all the way when listening to music then how would I be able to use the phone for regular voice? With a separate (Rockbox) device I can listen to music until the last drop of power goes out without hampering my communication abilities.
In my particular case, my phone’s lack of a proper standard USB port and it’s lack of anything but “full speed” (and yes full speed is less than high speed and is a lot slower than it sounds) when connecting it using the custom cable to my Linux box are two more reasons. Not to mention that it has this “database-only” approach to the music which I really don’t like – but yeah, I can learn to live with it.