Serves you right for watching Wranglerstar videos without a healthy sense of humor!
Yeah, you can 'wash' your chain in gasoline and leave the vapors out all night, then have gas soaked rags lying around, or you can do it in about 15 seconds with a water based degreaser and no fumes / fire hazard.
Are we 'the common man', or are we 'uncommon'? I agree that a lot of people who think that they can free-hand file accurately are not as good as they think they are. Lots of ways to sharpen a chain, and everyone has to find something that works for them. The Granberg 12V is one method - works for him, although, he ignores the other filing guides; most of his videos have a 'his way or wrong way' attitude.
But $15 to $20 to sharpen a chain!? You can buy a chain for that! $1,000 for a grinder!?! He has been inhaling too much of those gasoline fumes.
Flat depth gauges are not the best way, as noted. Best is to match the original, rounded profile. But at least giving attention to the depth gauges puts him ahead of a lot of guys.
He does not discuss his gullets much, but the chain shown is well used, and would need to have had some gullet maintenance done. Good to have nice, clean gullets to carry chips - some guys obsess over their gullets at the expense of the actual cutting edges, to the extent that some chains should be shouting out. 'Hey! Fella! My cutting edges are up HERE!'
I won't comment on his PPE choices (it is a sharpening, not falling video after all) - strictly his personal biases / preferences (or maybe his commercial endorsements, the way that he fawns over some of them).
Philbert
http://opeforum.com/threads/chain-build-off-rd-3-on-crs.731/ or is it all talk 
.
