I agree, it is nice to have a very clear high level approach to causal reasoning. I find his other books to be ‘slow going’ so I hope that after reading the Why book, I will have an easier time absorbing his earlier work.
I just started reading The Book of Why too, so far so good. I pre-ordered it once I found out it was coming. I've been telling people my view of it is it's like the primer to the primer (Causal Inference in Statistics: A Primer) to a subject-introduction paper (An Introduction to Causal Inference) to the OG math book (Causality). I'm hoping to eventually get back to the nice Causality hardcover I've had on my shelf for too long.