I think I noticed the same earlier on with Beta2, I just ripped the CDs to the harddrive and never payed any attention to it afterwards. That way you can just play them on any (capable) media director in the house.
If I understand webpaul1 correctly, it would probably require some changes in the way LinuxMCE handles media. With non-audio CDs (or DVDs) there are files on the disc which can be shared using conventional "network shares", audio CDs don't have these files but audio tracks instead. One option would be to stream those audio tracks seperately to wherever you want to play them, which is a whole different ballgame.
When the CD is ripped however, the audio becomes neat files on the harddrive that can be shared over the network in a conventional way. Since I reckon this is how most people use it I doubt there will be much effort put into making this work, but that's just my thought.