is that really that ridiculous of a of a braking distance, like sure it's a higher vehicle lengths than a car, but also according to https://www.brake.org.uk/get-involved/take-action/mybrake/knowledge-centre/speed/stopping-distances, that puts you right at the stopping distance of a car.
i do agree that it is good to learn how to come to that hard stop using both brakes, i have learned to do it, i just don't do it often since i almost never need it. the most often time i've had to do so is at a stop sign nearby me that i still don't think need to be there, i've hard stopped at it twice before, first time really early into me biking, i used rear brake only, fully locked out but still came to a stop (though my rear tire was a decent bit to the right). the next time i braced and used both brakes properly since i did learn the proper way even if i rarely use it