Different programming paradigms serve different purposes. Systems programmers prefer tools that are dumb, imperative and close to the metal. Enterprise programmers prefer tools which foster complexity, increasing billable hours and the client's dependency on the developer.
And, let me just come clean and admit it, functional programmers do it for that delicious feeling of superiority that comes from looking down your nose at the normals in their caves banging together for loops and mutable state to make fire.
Treat yourself to a crash course in the vocabulary of functional programming: higher order functions, combinators, the infinite opportunities to throw the word "monad" in the face of anyone who thinks an ironic moustache is enough to justify all that self-assured smugness these days. You'll never have to lose a programming argument again once you've learned where to casually toss terms like "applicative functor" and "Kleisli triple" into the conversation.
This is the War of the Hipsters. Arm yourself now, before it goes mainstream.