It’s in the name. It’s fast. You order at a drive-thru and you’re on your way in a couple of minutes. I agree though that prices are insane now and doesn’t justify the quality. I’d rather go to an asian restaurant for their lunch specials and get more for my buck.
Another thing I haven’t seen mentioned is its one of the last places open late anymore. I live close to a city, but if I need to grab something late (9:30+) fast food is about the only place open.