Bounce the cursor?

[Eli Zaretskii]

mouse-set-region has this fragment:

      (if (numberp beg) (goto-char beg))
      ;; On a text terminal, bounce the cursor.
      (or transient-mark-mode
          (window-system)
          (sit-for 1))   <<<<<<<<<<<<<<<<<<<< ?????
      (push-mark)

Why does it call sit-for only on text terminals?  Is there some
assumption that the region dragged over is not highlighted in color,
or am I missing something?