There are pros and cons of each media, I'm not arguing against it. What I mean is that there's a general tendency of migration from longer versions( books) to more compact,bite size content(videos). It's one of the reasons why there's countless videos on YouTube on how to create a dictionary in Python,even though the documentation has it covered wide and deep.
I agree that something like a Python dictionary is probably unnecessary to make a standalone video for, but simple concepts like that also wouldn't be a 3000 word article unless you're looking for literally every nuance and weird quirk the language has to offer.
Haha, I'm genuinely intrigued to see the contents of that book. It could certainly be copy/paste from the Mozilla docs, but who knows! I was pleasantly surprised by this video about the JS event loop, although in fairness it is a lecture at a conference rather than a made for youtube video. Regardless, the length of the video made me question how necessary it was but I ended up watching the whole thing and enjoyed it. https://www.youtube.com/watch?v=8aGhZQkoFbQ