The alternative would be for you to stand on the brakes whilst making an evacuation decision, setting it then if not forgetting it (much more dangerous).
subjective really,an aircraft that is stopped does not require much braking force if any at all and should not drain any captain brain energy away from an evacuation decision..
For the 'forgetting ' issue refer to the Evacuation
CHECKlist.
One other difference between carbon and steel brakes that might be evident in certain RTOs is brake welding. Steel brakes, which usually have rotors of steel and stators of a copper-iron mix (with a number of special ingredients) can weld together, preventing further wheel rotation. This can even happen before the airplane comes to a full stop, particularly in the last several knots where the antiskid system is not effective.