Who says that "Mostly functional programming" sets out to control side effects? How the hell do you get to the conconculsion that's it's no more useful than s

Who says that "Mostly functional programming" sets out to control side effects? How the hell do you get to the conconculsion that's it's no more useful than standard imperative programming? That implies that e.g. first class functions do not have merit, which is, excuse me, horseshit. Lisp doesn't do that and it works wonderful. Same for ML/F#, PerformunsaveIO, Ocaml, you name it.