An analogy of what you said:
It's similar to HDR for audio[1] (but not exactly like it). HDR can be used for photography that, once composed and edited, will present more realistic information to our eyes. For example, with HDR you wouldn't have an overexposed sky - however the HDR is only used in order to get to that final 16 bit image (and even with 16 bit your eyes have a hard time discerning different colors).
The same applies to audio. Listening to 24-bit is pointless, however, if you are editing something you want to retain as much information as possible until the final render so that you don't run into clamping issues as you described.
Therefore, sites that provide 192/24 downloads are valuable. If I'm a DJ getting music for my gig I do want those production quality files, as I cross-fade between two songs I don't want artefacts popping (excuse the pun) up.
On to my own opinion: 24-bit is still not good enough. DAWs should be working in floats. Audio needs to go true HDR, 24-bit is a cop-out. Why would you even used a 24-bit int when floats are there and ready to go? Imagery went floating point, what, 10 years ago? Why can't audio catch up? Being able to exceed the clip in my DAW in a channel, and then wrangle it back down in another would be awesome.
Unrelated: That Xiph video really amazes in terms of what nature does. We rarely care about it (we do in terms of e.g. intercontinental fibre cables), but nature does all of this when we send a signal to a speaker. Even normal sound does actually have a band limit and does behave (albeit, far higher dynamic range) exactly the same way automatically. Shoot a signal down a fibre cable that can't handle it, and you'll get Nyquist. Too high frequency for RTP air? Expect distortion (that we can't hear). You don't even have to include electronics to get nature to impose these limitations for you, you have to do no extra work. Completely amazing - a deeper level of logic that is mind boggling.
[1]: http://www.slideshare.net/DICEStudio/audio-for-multiplayer-b...