Today, we had an issue with a mouse and wanted to halt a computer through keyboard so I immediately thought of the nice new feature to call system actions through overview. So we tried "stop", "halt" but the action would not be made available in overview. In the end, I had to check another computer with a mouse to see that the dialog name is "power off". Hence we finally tried "power off" and got the action (later I also discovered that "shutdown" works, I didn't think of this one immediately).

Expected result: "halt" and "stop" could be alias/keyword for the "power off" system action.