Hey Tommy, I believe this is what's called a "Music Video" they had them on TV for a while before the days of reality television.
Putting up my own video recordings I've always thought how much more difficult it would be to try and record, then listen to what I played and try to play exactly the same thing for a video, but sometimes that's the only way to do it if you are using a backing track.
I personally haven't been able to figure out how to edit this sort of thing together, maybe when I make it big as a cajun accordionist I'll be able to afford Nick to edit my videos...
Yup, if it is a music video it is there to entertain not to instruct.
Over dubbing and blending are used for the entertainment value. Unless it is recorded live, with all the "oops" that could not be edited out, it is adjusted to give the customer the best sounding performance.