[racket] to local or not to local

Hi.

In the web-server related documentation, I see the preferred way to
create local procedures as

  (define (start request)
    (local ((define (response-generator...))
            (define (some-handler...)))
      (do-something-with-these)))

Another way to create local procedures is

  (define (start request)
    (define (response-generator...))
    (define (some-handler...))
    (do-something-with-these)))

Is there some (subtle?) difference between these approaches?
Which way is appropriate in what conditions?

Thanks,
s.