Who is the world's fastest roofer? Is it this guy? Maybe. His installation of 15 square in one day is certainly impressive. I'll venture, he might be the fastest hand-nailer. So far (at least, faster than this guy). But based on what's in the video, this guy is faster with a nail gun.
Still, my bets are with this guy. Why? He doesn't just work in the middle of the roof, but starts at the eaves, which we have to do in the real-world. And he has to reload his gun, which is another fact of life during the course of a day. It's true, they still haven't invented a gun that doesn't run out of nails.