A big part of keeping the coolant temperature low is to be able to run more ignition timing and make more power. Or at least consistent power from run to run.

Years ago, I ran a dragster that didn't have a radiator or water pump at all, as most did and still do. The normal procedure in any weather was to dump the coolant between runs. Sometimes twice. And no way could you "hot lap" that kind of car especially in the summer.

Also, spraying the radiator with water between runs is useless unless you are circulating coolant. That's why most doorslammer race only cars have an electric water pump that can be run when the engine isn't running and generating heat. Unless you go to a lot of trouble these pumps don't push the kind of flow that a stock style belt drive pump will. And often, it's shut off during a run, as it won't make any difference in the few seconds that it takes to make a pass.