Why use such a high sample rate?
Well, for me pretty much the only reason is because some effects and synths sound better at higher sample rates.
There was a thread at kvr which dealt with this issue, you can read it for some explanations:
The upsampling your mix thread
But basically the problem is: some effects/synths introduce aliasing and aliasing sounds bad. By using a high sample rate aliasing is moved to higher frequencies where us humans can’t hear it. (I’m no expert so if I’m wrong here please correct me.)
Anyway if it’s not difficult to implement it would be nice to have that option. And 88kHz could be useful as well, since it’s 2x44 (for easy conversion) and a lot of people use it.