Technically, reduce covers map, flatmap, filter, etc. It's every bit as flexible as a for-each loop (the only difference is it implies no side effects, but does

Technically, reduce covers map, flatmap, filter, etc. It's every bit as flexible as a for-each loop (the only difference is it implies no side effects, but does not guarantee them if the language doesn't). The very reason those other functional constructs were split out was not due to need, but due to -clarity-. And that same clarity applies to why to use one of those constructs instead of a for-each loop.