And then there is the processing issue. As you said (one more time), when you start processing stuff these extra bits of precision may help preserving the quality of the signal you are producing. So, even if you are producing 16 bit audio, it's good to process it in 24. But I'm not sure actually recording stuff in more than 16 bits is possible, because it's very hard to get not only a decent microphone, but to build a room that quiet.D