Map, fold, reduce and friends are statements of intent, and reading a line of transformations composed on multiple maps and such is generally much clearer than

Map, fold, reduce and friends are statements of intent, and reading a line of transformations composed on multiple maps and such is generally much clearer than reading a series of loops in which you have to figure out intent by looking and what's going on inside each loop. Also, error density is relatively constant per line of code according to most studies (this is a very general statement, but we can assume that most code just isn't trying to be clever). I've forgotten to add(), append() and drop items inside a loop far more than I've made mistakes inside more functional methods.