My (heretical?) opinion is that videos are a waste of time compared to text for the majority of content and the majority of people. There are some ideas that can be very nicely visualized and some people (e.g. dyslexics, non-native speakers) who struggle with text. For the rest I think text is better.
I disagree strongly with this opinion. Videos and text can play different roles in the comprehension of ideas.
My experience is that if I'm comfortable with a topic, text is far more effective as a medium to absorb knowledge from. For learning programming languages, for example, I've found it much more effective to read books that to sit for lectures or online videos.
However, for topics like complex mathematics or algorithms, especially with dense terminology, text often appears like an impenetrable wall of text for me. Good video lectures help me see through the professor's thought process and divide the problem in smaller, more comprehensible parts.
In my opinion, the strongest advantage of video content is that they include an element of guided attention. A good video can forcefully mute the secondary details and highlight the essence of a concept or process.
I can see how you can spend hours on videos and not learn a lot though. After getting an insight from a video, the concepts need to be practiced through exercises, which is active as compared to passive watching, else the advantages are lost because the information can be easily forgotten.
I find videos terrible for learning on their own. But combined with taking notes, reviewing them after, and using them to kick off a bit of reading or (better) experimentation, they can be an invaluable part of the learning process.