Fine then lets do this.
Granted that the weak link in the recording chain (a microphone for instance) will limit the possible recordable fidelity, most likely well below the 16bit threshold, I find that to be beside the point. Nor is there any way that, given the same sample, the human ear can hear the difference between 16 and 24 bit. It simply goes beyond, and well beyond, the auditory acuity of any human being.
The advantage, "in my opinion," has only to do with extensive processing, i.e. the adding of effects and filters, mixing, re-sampling, etc, and specifically if working entirely in the digital realm (which adds effects based upon the manipulation of digital data). More data, in this case, affects the ability of a computer to discreetly edit/filter data without deteriorating the sound quality. Editing will fade into the background more smoothly and be more effective at producing the desired results if it has more points to work with.
One could expect better results from adding filters in 24bit even if they simply expanded their sample from 16 bit, and then moved it back for the final cut. This would be less desirable, of course, than to have recorded in 24 bit to begin with.
I guess what I'm trying to say is that even if your equipment kind of sucks, if you plan to screw around with your samples a lot, 24bit is not a complete waste of time.