Imagine that you are a trucker running along in a big convoy of about 20 trucks. 53 footers loaded to the hilt. Most of the trucks have the standard air brake setup of the day including your rig. But 2 or 3 of them have that new fangled electronic/hydraulic/air/computer controlled braking sytem with auto correct. It reacts and stops about 30% faster than the normal setup. Are you going to want the trucks with the new technology rolling in front, or behind you? Same for the disc vs rim brakes. Every rider in the race has to have the same kind with the same stopping ability. It doesn't matter which as long as they are the same. The safety issue comes up when they are not the same and provide different braking characteristics.