Why should shell-command-on-region call kill-buffer?

Specifically, in the no output case, you have: (let ((lines (save-excursion (set-buffer buffer) (if (= (buffer-size) 0) 0 (count-lines (point-min) (point-max)))))) (cond ((= lines 0) (if success (display-message 'command (if (eql exit-status 0) "(Shell command succeeded with no output)" "(Shell command failed with no output)"))) (kill-buffer buffer)) [...] What is the reason for that kill-buffer? I see nothing in the documentation telling that the no output case is special... OG.