I have not seen any of those videos, but I believe any course should first discuss the gun design and how it works.
Then, if it is a course in, say, accurizing the M1911 type pistol, it should show how the changes affect the functioning, how to use a bench block, how to use hammer and sear blocks, how to use a stoning jig, how to harden parts, what other tools are needed, discuss long recoil spring guides, show how to fit a barrel bushing, show how to fit a link, etc., etc.
As you can see, this is a lot, and this is just one aspect of one pistol. Can a video tape teach even a little of this? I doubt it.
Maybe if all you want is to learn to take off a sideplate and clean a revolver, or take the slide off a SIG, a video tape can teach it. Beyond that....
Jim