One benefit there if it's statically typed is that you've pushed some correctness validation into the compiler. In dynamic languages like Clojure it is far too

One benefit there if it's statically typed is that you've pushed some correctness validation into the compiler. In dynamic languages like Clojure it is far too easy to couple functionality and write implicitly imperative but superficially functional code. Something I'm guilty of because it's too easy to do and takes a lot of experience and discipline to avoid.