[tmtvl]

In terms of speed, yes. In terms of functionality, hell no. Compare the following in Racket:

  (define (add-2 x)
    (+ x 2))
  (add-2 z)

Where the result is an error without the possibility to provide a value. Compared to in SBCL:

  (defun add-2 (x)
    (+ x 2))
  (add-2 z)

Where we are dropped in the debugger with the following possible restarts:

* Continue, where we retry the operation (best to first define z),

* Use Value, where we can provide a value to use,

* Store Value, where we can set z to a value and use the value,

* Abort, where we just cancel the operation.

There's also setf expansions, so in SBCL we can do, for example:

  (setf (car some-pair) 3)

Whereas in Racket we can't do the equivalent:

  (set! (car some-pair) 3)