Actually noise performance could be improved non-trivially in a binned environment. Basically you are working with 4 times the number of data sources, so the random variance because 1/4 as strong. I'm definitely not using the right terminology right now (you'll have to forgive me, it's been a *very* long day at the office), but I did want to respond with a general direction of what I'm thinking. I'll respond later tonight or tomorrow in more detail if you would like, but long story made very short, you have 4x the signal to 1x the noise in a 4:1 (2x2) bin. That is significant.
I understand that binning increases the signal/noise per pixel, but my point is that the binning doesn't need to be in camera. You can later bin the full resolution raw image in software with the same noise improvement. But perhaps you were referring to some other advantage?
(the S/N will improve 2x for 2x2 binning: the signal increases 4x but the noise only 2x because of the tendency of random noise to "cancel out" when you add it up - that's why adding up 4 noisy pixels only gives twice the noise as a single pixel)