Agreed. There's a reason why we need to sleep.
I went for a 9days St. John training camp, maximum only get 3hours sleep per day. No luck on sleeping on classes coz everyday have to run around solving puzzles and collecting stamps, building bamboo towers and doing many other stuffs. Oh and if the trainers caught you dozing, then it's whole group pumping 20 times or running laps around the field. On the ninth day, I found out what it really meant by microsleep. I can talk or listened to some conversations, blackout for 1 or 2 seconds, and then continue talking without realizing I've actually stopped talking.

Yes it's called Microsleep.
That's why it's dangerous to continue force oneself continue driving even though already very tired.