There's a lot of stuff in there, and it is very compelling, but there is really only one take-away from it:

Get lots of sleep.

The book is mostly helpful for people who try to "optimize" things or rationalize why they don't need to follow the rules. He debunks all of the excuses.

If you already get enough sleep, then you don't need the book.

Yes, if you have any interest in sleep or the role it may play in the onset or progression of diseases like Alzheimer’s, cancer, cardiovascular issues, diabetes, etc.

I’m only midway through it, but I could see how some of the material could seem redundant or sensationalized if you’re not at least somewhat interested. However, the author does a great job of summarizing studies and presenting data when something seems like it could be sensational. E.g., The heightened rates of heart attacks, car accidents, etc. the day we ‘spring forward’ and lose an hour of sleep in the U.S. for DST (whereas fewer cardiac events, accidents, etc. happen when we ‘fall back.’)

I haven’t read the book cover to cover, but I’ve heard him talk and read summaries. If it’s something you’re interested in, he’s definitely an authority worth listening to. It can also be very useful to diagnose/help friends and family that might struggle more with sleep and not even realize that it’s the downstream source of their problems

You're on HN. You've got a curious mind. Isn't that an interesting question? Why do we sleep? There's been some good progress on trying to answer that. It doesn't just have to be some binary answer, there's a lot going on there.

If you're pragmatic then increasing quality of your sleep may make it worth reading.