FP Scala Meat & Potatoes: HTTP, JSON...

It's great to talk about free monads vs. finally-tagless, monads vs. applicatives, fixpoints and recursion schemes, category theory, etc. but does pure FP in Scala have anything to offer those of us who just need to receive some JSON, talk to a SQL database, and return some JSON? Come for an (almost) jargon-free look at why pure FP matters even in such meat-and-potatoes tasks, and for some hints as to how this relates to some of the more esoteric uses of FP some of your colleagues may be up to, or you may want to pursue later.