24bit also means we don't have to record at 0dBFS, which saves a lot of time.
By comparison, 16 bit audio can "only" record a whisper in a library and a motorcycle or jackhammer.
Double blind tests show that 8 bits are not enough, but 14 bits are.
You're right of course that it will compress less well, but that's to be expected because you've lost less information!
Store the 24-bit signal, and you could do a dithered downsample to 16-bit on playback if you think that's a good idea. Wouldn't that be better all round?
For playback though, I agree that 14 bits are probably enough. Even high quality mastering tape has the equivalent of about 12 bits of dynamic range, which is fine. Many fabled analog pieces of equipment have terrible signal-noise characteristics, but are still valued for other reasons (coloration, distortion etc...)-which is all fine by me.
If you have the time, watch the two videos that xiph.org did a few years ago. There's a great in-depth explanation, as well as a hands on demonstration to demonstrate this reality.
I got a Denon one. I haven't played any SACD on it yet (I got it for bluray), though I guess I could easily find some at that video rental store (in Tokyo).