I am not sure what you mean by "only as data". Data is the only thing you can store on a disk. You can store mp3s on a recordable DVD. Clearly with 4.7 GB of space you can get a lot on a disk, and if your DVD drive supports DL (Dual Layer) disks then that figure is nearly doubled to 8.5 GB. This is useful for storage and in fact you can use such a disk in many home DVD players these days. I have a fairly cheap Toshiba DVD player (it cost around 40 UK pounds, a bit less than 60 US dollars) it has RCA stereo sockets for hooking up to a hifi and optical output and it will play mp3s off a DVD burned as a DVD-ROM disk. You get an onscreen menu and you can set up a play list, which is great for parties or for using like a juke box. I organise them into folders by albums. You have to use a burning app like Nero to do this, I don't mean the Windows drag and drop method.
Did that answer your question?