I always wondered what the point was in cue/bin CD images compared to the ISO format, but never bothered to look it up.
A couple of days ago I was looking for music from an old Playstation game (which I own but couldn't be bothered to track down). I knew the music was on the disc as CD audio since I'd copied it to tape a dozen years or more ago, so I found and downloaded an image of the game from the web.
The thought then occurred -- how do I rip the music from this image? I usually use cdparanoia to get music off CDs, but could I point cdparanoia to a mounted CD image? The answer is no -- I would only be able to mount the data partition. You don't mount an audio CD before ripping music from it, cdparanoia just accesses the drive directly. Would I have to burn the image to a CD, then rip it back onto the machine? That's ridiculous.
Meanwhile the download finished and I saw that it was bin/cue rather than ISO. This is when I looked it up. It seems obvious now, but an ISO is just the ISO-9660 filesystem -- the data part. As such, an ISO file can't include CD audio. The bin/cue format is needed in order to include the data on the separate tracks of the CD. Converting the bin/cue to ISO would have lost me all the music.
So for future reference, extracting the audio (and the ISO at the same time) from bin/cue is as easy as this:
bchunk -w wild9.bin wild9.cue wild9
-w there makes it write any audio as wave files so I can then convert to Flac. I assume it'd write them as raw PCM otherwise, but I've no desire to check.