I've never used one personally, there was only two times where I've seen it in action:

Once in HS when I was on a school bus, this kid was smoking on the bus. The driver said put it out or he'll put it out for him. Kid was being a prick so the bus driver sprayed him in the face. It was like a powder.

Other time, probably around that time period, my mom was cooking pot roast in the broiler (bottom-most part of the oven) when she was taking out the roast, this hanging towel caught fire. My brother sprayed the pot roast :facepalm: