I agree with the resolution issue, but its is pretty cool to pick up flaws in a recording, be it in ambient noise, room noise, or trying to figure out if it really was Robert Plant or someone else coughing at the beginning of Whole Lotta Love.
More important than 24 bits is the quality of the recording, you need to be careful still. It is just as much fun trying to research the good 24 bit recordings as it is trying to find good redbook recordings that aren't brickwalled. It sucks to pay a premium for a 24 bit download that is compressed to the max.