In the toolbar, there is a quit button that isn't necessary since there is a close button in the window title bar. Reproducible: Always Steps to Reproduce: 1. Open System Settings 3. Open another program, such as Rekonq Actual Results: System Settings has Quit button but other programs such as Rekonq do not Expected Results: All applications should standardize on this and not have a Quit button in the toolbar.
We got a bug report when it did not have a way to exit (see bug 171915), so the quit button is intended.
I agree with you that it seems pointless, but I guess you can't please everybody. Wontfix. Sorry