The author presents succinct and compelling reasons to prefer functional principles. To add, I find the strong push for purity of functions helps free up the p

The author presents succinct and compelling reasons to prefer functional principles. To add, I find the strong push for purity of functions helps free up the part of my mind which seems to constantly worry about potential problems or unknown/unexpected behaviors. With that background noise out of the way, I can create more elegant (by my own judgement :) ) solutions to needs. I also sleep better.