One might be underestimating the value that video lectures offer to certain people like myself. Reading a textbook demands to be proactive. If you are easily distracted, or don't really enjoy the subject, you have to force yourself to keep reading. In the case of video lectures you only have to bring yourself to start the video. Once the video is playing, your attention is naturally drawn to the ongoing action, whereas text is just inactive and has to be animated actively by the reader. Videos exhibit a tractive force, videos drag you along as they play.