It is a major characteristic and it is positive. I work with backend services in clojure, we have a huge codebase and many programmers working in parallel in the project (6 right now). The code is straight forward, short and elegant with immutable functions and some few macros. It's the first time in my 10 years programming career that I can say that about the codebase I'm working in. I agree that it's hard to understand the benefit if don't know FP to some degree and don't have much experience working with it (Paul Graham blub paradox).