Interesting, why would you summarize the book, if the whole point of reading it, is reading it?
A man once told me, if the book is boring to you, just leave it, no need to read it full. Not every book is interesting, turns out.
The other case, if I find boring parts within the book, I just skip them myself.
In the end, give the state of LLM, I would be afraid that I'll miss some interesting parts or get things that are not true.
What I think LLM would be useful is excatly the thing you said its not - summary. I would love to get a summary bullet points every chapter or every few pages. That would be really useful.