Using temporary buffers to display messages

["Óscar Fuentes" <ofv@wanadoo.es>]

`sunrise-sunset' contains this code, that displays the text on the
minibuffer if the frame is wide enough and on a temporary buffer
otherwise:

(if (<= (length msg) (frame-width))
        (message "%s" msg)
      (with-output-to-temp-buffer "*temp*"
        (princ (concat date-string "\n" time-string)))
      (message "%s"
               (substitute-command-keys
                (if one-window
                    (if pop-up-windows
                        "Type \\[delete-other-windows] to remove temp window."
                      "Type \\[switch-to-buffer] RET to remove temp window.")
                  "Type \\[switch-to-buffer-other-window] RET to restore old \
contents of temp window."))))

Is it correct nowadays to use a temporary buffer for displaying
informative text when it doesn't fit on a single line or is it a vestige
of the times when the minibuffer lacked autoexpand capabilities?

(There is another issue with the code above: if the minibuffer is on a
separate frame with different width, the function may end displaying the
text on a way that is not what the original developer intended.)