What is being used in the video is pork jowl, known as guanciale in Italian (basically cured pork cheek) . It has a high fat content, even compared to pork belly. Fat is flavor, so no convincing from butchers is required. Also, it's a cheap cut, so if they want to make money off their customers, they'll want to also sell things like Secreto ibérico, or better yet, jamón ibérico de bellota.

Is Italian not traditionally food that poor people ate? They often made due with what was available.

And thats Guanciale, or pork cheek. Not pork belly.

Way too fatty for dogs.