Does Scheme even have NIL in the sense that other Lisps like CL or Elisp have? I mean in Common Lisp, we have:

  CL-USER> (symbolp nil)
  T
  CL-USER> (atom nil)
  T
  CL-USER> (listp nil)
  T

Similar results in Emacs Lisp. But in MIT Scheme, we get:

  1 ]=> nil

  ;Unbound variable: nil

Of course, we can use () or (define nil ()) to illustrate your point. For example:

  1 ]=> (car ())

  ;The object (), passed as the first argument to car, is not the correct type.

But when I said NIL earlier, I really meant the symbol NIL that evaluates to NIL and is both a LIST and ATOM. But otherwise, yes, I understand your point and agree with it.