I mean, it can be, right? Take todays Advent of Code problem, where you want to grab the index of the largest element in a sequence breaking ties toward early elements, then re-distribute that element one at a time over other positions starting from the largest element (looping around as required).

I can write that using various maps, folds, flat_maps, and reduces, but no one else would understand what is going on in the code. Maybe someone will post the right idiomatic functional way to do that, but nothing elegant comes to mind.