I retired this year, but my last job was managing a deep learning team. I know many people who own this book, but no one including myself who has read it. Personally, the value I got from it was the first section on math, then picking and choosing limited material that I used for a reference or overview.
I read it! But then, I love reading technical books.
I did find that it didn't provide much context around why the equations matter, and definitely wouldn't be useful for those starting out in the field. It did have some pretty good coverage of gradient descent and various optimisers, which I found useful.
tl;dr: not really worth it for its stated purpose, but not a bad second or third stats book.
