What's up with apply-partially?

[David Kastrup <dak@gnu.org>]

The original definition of apply-partially in subr.el by Eli in 2008 has
been

(defun apply-partially (fun &rest args)
  "Return a function that is a partial application of FUN to ARGS.
ARGS is a list of the first N arguments to pass to FUN.
The result is a new function which does the same as FUN, except that
the first N arguments are fixed at the values with which this function
was called."
  (lexical-let ((fun fun) (args1 args))
    (lambda (&rest args2) (apply fun (append args1 args2)))))

The current definition by Stefan, however, is
(defun apply-partially (fun &rest args)
  "Return a function that is a partial application of FUN to ARGS.
ARGS is a list of the first N arguments to pass to FUN.
The result is a new function which does the same as FUN, except that
the first N arguments are fixed at the values with which this function
was called."
  `(closure (t) (&rest args)
            (apply ',fun ,@(mapcar (lambda (arg) `',arg) args) args)))

Now subr.el has lexical-bind set.  It seems quite pointless to return
some unevaluated quoted list here (apply-partially is not a macro but a
function!).

So why not just

(defun apply-partially (fun &rest args)
  (lambda (&rest args2) (apply fun (append args args2))))

Where is the point in the complicated redefinition that returns a
basically uncompiled function?  Why not just take Eli's definition and
simplify it in line with lexical-binding now being set?

I don't understand the point of the change.  Lexical bindings should
have made this function more straightforward.  Instead it has become
more complex and unevaluated.  And it's not like describe-function even
knows `closure', as opposed to `lambda'.  So it's become inscrutable as
well.

-- 
David Kastrup