Many non-fiction books, you can get the gist by reading a blogger's summary, but I think the length of the book actually gives my brain time to digest and commit to permanent memory the idea(s) in the book.
Reading a 3 minute summary, once, I will easily forget the knowledge. But reading about the idea with different stories and other auxiliary information help me retain the principles much faster.
Its not only the idea, but the history, and analysis of the author.
Reading a book is not just “downloading a knowledge into your brain”.
Reading is more like executing a program and seeing dofferent result in dofferent people. People will reflect in a different way and come out with different takes, emphasize points, lessons, and takeaways
I feel the exact opposite. Slogging through all irrelevant filler in those books dilutes everything, and makes me impatient and unfocused, just fast-forwarding through.
Crossing the Chasm can basically be summarized in a page or two. There's probably some value in actually reading the book if it's relevant to your space.