Interesting, didn’t consider binning the pixels in hardware but it makes sense that it would lower read noise.
After thinking this through a bit more I wonder how they low pass the image before sampling it with binning. 12mpix without any optical low pass filter sounds like a lot of aliasing. Maybe they ‘hack it’ using the optical stabilization system to vibrate the sensor a bit. 
Anyways I guess we’ll have to wait and see how it actually works and performs.