But machines aren't (yet) as capable as humans at driving-situation-recognition and driving-decision-making. One way they can compensate for those shortcomings is to be superior in other ways: 100% vigilance and super-fast reaction times/decision-making.

Answering my own question. Possibly industrial applications like detecting objects on a fast conveyor belt. A recycling facility for instance.

100ms is generally considered to be the lower bound for a valid start, i.e. 99 would be considered a jump start in F1 iirc

No, that's only if you want the human to be able to make the reaction. If the application was self-driving, you'd prefer the car to react faster than a human. For a military application like projectile detection to avoid or destroy the object, you'd want something even faster.

I'm not sure what your argument is. Any self-driving system should strive to be much better than human drivers. It makes complete sense to have reaction time much better than human.

For reference I am making a farming robot that goes at 1 meter per second and I run the main control loop at 10hz. I would absolutely run a car that goes freeway speeds at at least 100hz.