> In order for it to be even theoretically possible to hear the difference between 16-bit and 24-bit audio,
Only for professionally mastered audio which is not a safe assumption in this day and age. If some home engineer recorded a track with too much headroom and you get the 24-bit track you're fine, at 16-bits you have a problem.
I would love a music player where I could play tracks at 88kHz/24-bit because that's what most music is during the mixing process and then an audio engineer can give you the raw version of what they're working with without having to deal with issues of headroom, downsampling and dithering.
24-bit audio doesn't hurt anything other than file size and it has real uses, be it remix culture or just high-quality unmastered music.