This video, actually:
I'm not a shoemaker, but I have seen goodyear welt machines at work, as well as handwelting, and it definitely seems like this guy is simulating goodyear wetting, by hand.
It's not an insane concept. There are a number of Japanese companies that seek to "Put the human into an industrial process". Hender Scheme, for example, makes pretty faithful copies of iconic sneakers like the Air Force 1 and Nike Presto, but using natural leather and traditional shoemaking techniques. Or maybe it's a little crazy, but also super cool.
That looks like handwelting to me, and I can't see any gemming. But I also am not a cordwainer, so maybe I just can't see it.