Hi,
It was an enjoyable watch ... no doubt about that. It usually is, although one does not really learn how the musician got his results, and this is better shown in a film like "It's Gonna Get Loud" when you even get small discussions of how something brought out something else ... although, nowadays, I am not sure that a special guitar will show as much as it could have 40 or 50 years ago, since so much stuff these days is computerized and from a DAW, and not necessarily an instrument.
I was asking a friend, if he played one of the basses in Trillion, and then his own, would an outsider know the difference? He said he doubted it but there would be a side of it that could help you define it, and it would be playing details ... strings bend, stretch, the finger sticks and clicks, the little things that can add to the piece that he can see on his recording from listening, but an audience would not have any idea. But that for the most part, few people would know the difference, and nowadays, you can treat a guitar so much, that no one can determine pretty much anything.
I think that we will be entering a phase in music history where the individual ability to create something is going to be hidden more and more ... and hopefully we can get it back ... someday.