The guy in the video carries full sized, double stack, nine millimeters. He also said in the video that most people can carry a bigger gun than they think. Seemed like he was trying to encourage carrying the most substantial handgun a person can figure out how to comfortably carry and conceal, and to try to carry a bigger gun if you're currently carrying a mouse gun, or even a compact/single stack 9mm or J-Frame .38.
I've never heard anyone who had been in a gun fight EVER complain that he had too much gun. I've read countless times where someone carried something small, got into a gunfight and after that always carried something larger.
One advantage of a full sized pistol beyond caliber or capacity is the fact that 9 out 10 people will shoot the full sized pistol better than a compact or sub-compact. So the moment you pull your gun your confidence level is already higher.
I've been carrying a full sized auto since I can remember, and it doesn't bother me at all...but that's me. It's not for everyone, and I don't feel a "self calling" to belittle everyone else into doing so.