I can confirm that Halon is awesome.
I bought some little one pounders for about $ 24 each years ago.
I had a real opportunity to one..
it instantly stops fire.
I don't think it does it by just displacing oxygen either.

I had a couple of inches of gas in a yogurt container , on fire.
One short instantaneous blast of halon ..like a micro-second.'s worth. .
fire gone, , nothing burnt , over an inch of liquid gas still in the
yogurt container.
Slight warping of the yogurt container's plastic is all.
And no mess to clean up either.
It was banned or changed due to environmental factors is my understanding.