Why C/C++ for system programming?

It is unsafe, verbose and not particularly fast. Why I'm writing much more readable code with Lisp, using the same API?

Lisp:

(defun folder-p (path) (w/opendir (dir path) (not (null-pointer-p dir))))
(defun file-p (path)
  (unless (folder-p path)
    (w/fopen (f path "r")
      (not (null-pointer-p f)))))


C/C++:

int folderP(char *Name) {
  DIR *Dir;
  struct dirent *Ent;
  if(!(Dir = opendir(Name))) return 0;
  closedir(Dir);
  return 1;
}

int fileP(char *Name) {
  FILE *F;
  if (folderP(Name)) return 0;
  F = fopen(Name, "r");
  unless (F) return 0;
  fclose (F);
  return 1;
}

You can have very fine grained low level control in C and C++. Which Lisp dialect permits this and also integrates with existing libraries of code (so you can spend time on the important stuff and not reinventing the wheel)?