It was intended to corroborate and to point out a difference that helps to explain why Tk replaces exit. My understanding of the two is from the documentation and my experience, which does not include Tk on Windows, so the difference I know about is that Tk::exit reliably destroys all of the MainWindows, while CORE::exit allows a forked worker (such as performing an LWP request without blocking the GUI) to safely exit after reporting its results back. On X11, calling Tk::exit from a forked child also causes the parent to exit.