For some things (visual, hands on) they make sense, especially for long and complicated tasks (I've used some for complicated tasks in software like blender or how to do lost wax casting - stuff like that). For short, simple tasks, it's more hassle than it's worth.
A block of text can be read as and when you need it, copied and pasted in to a window and read alongside - it's portable, semantically useful information. An instructional video showing you how to play a particular song on a guitar (of which there are many) is too much information in an inappropriate format - tabulature is as simple as possible and is easy to print out or view on the screen.
A video (like a phone call) intrudes and demands your attention rather than just giving you the information. You can't use
it, you have to sit still and absorb it.
But as +Michael Richter
Said ' -site
'. Problem solved.