Originally Posted by Mose

It would limit the size of the crash if riders could stop quicker. And yes, especially in wet conditions at higher speed, front brake lacks stopping power. Rear is almost no use, I wouldn't be surprised if the set up became disc front, side pull still on the rear.

I used to ride a mountain bike without a rear brake because after a while because I never used it. Then race officials started noticing and getting picky about it.