When we provide written documents with embedded videos revealed by on-screen toggles, covering different sections of a help document, almost no one reads the doc, they just find the relevant video. Many of our docs require images, and videos do a better job of, for example, showing how to clamp an arm onto a structure.
Video that cover different parts of an outline are a great use of videos. Videos that try to cover too much all in one are a lesser use. Yes, you can use scrub to find in a video, but showing a text outline and letting users click to reveal videos for specifics topics works very well.