My biggest problem with most of these libraries is the complete lack of care for efficiency, and some packages use more of these functions than builtins. eg. -map is identical to mapcar (a C primitive), but instead of defining it as a defalias, its defined as a defun that just calls mapcar on its args. Function calls, especially of bytecode, are very slow, so now instead of just a single primitive funcall, there's a second bytecode funcall that does nothing. this is done in a lot of places in dash and especially in s.el. plus, while the compiler will warn when mapcar is called for effect and advise using mapc, it doesn't know about -map, and ive seen it called for effect a lot.