The wonderful thing about .reduce() is that it can compute literally anything. The problem with .reduce() is that it can compute literally anything. As for the rest of the morphism menagerie, I like being able to break up functions and pass intermediate results around. It's literally cut and paste with map/filter, with a loop it's rewriting. Yay composability.

That said, it's easy to get carried away, and some devs certainly do. I used to be one of those devs, but these days I sometimes just suck it up and use a local variable or two in a loop when the intent is perfectly clear and it's not leaking side effects outside of a narrow scope. But I'll be damned if I let anyone tell me to make imperative loops my only style or even my primary one.