Those extra seconds add up and in my opinion readability is more about optimizing reading speed by using common shapes and patterns conventionally, not making something dumb proof.
It even suggests using a dependency like underscore for something that is already in the language. So if I don't use underscore, I need to stop my reading completely because my mind doesn't recognize this _(array).contains('foo') pattern and I need to actively read the entire line and in cases lookup the documentation of some random method in a random obscure _ library that I also need to lookup in the code to find the actual dependency name. Because even if I were to check the implementation of that underscore method using the IDE, it's even more obscure and magic. Good luck following the advice in this book.