I keep going back to the Sega CD example since I used to play them in there then because A: CD players weren't cheap (although neither was the Sega CD) and B: It was a real novelty to get CD quality music back then. Many games would put all the data on track 1 and then put all the music on the others so you'd get these great soundtracks that could also be put in regular CD players. It would get a little weird though. Some games seemed to just put stuff there because they could. I remember Lunar: Silver Star Story had dialog tracks for cut scenes in the audio tracks, so if you listened to them you basically got the entire story in advance (I speak from experience sadly.) Speaking of, Lunar 1 & 2 are SADLY underappreciated RPG games and I do wish they'd bring them back on something other than portable devices.I don't know if I have ever used a gaming console to play CDs. I did rip CDs to the original Xbox for custom soundtracks. I also used network streaming quite a bit on my 360 for background gaming music. I don't need CD support but I really would like MP3 support over the network.
At the very least I would like to be able to play music off a USB flash drive or by plugging my iPhone in via the USB cable. You could plug the old iPods in to the 360 and get custom soundtracks that way but I don't think that worked with iPhones.