Imagine, you add an object to the scene and you get the redo-panel (F9 menu). If you want to modify the options of the newly created object but you mistakenly click elsewhere, the menu disappears. That's not a problem, since you can bring back this menu using F9.
However, imagine you move the object (using G) first and then want to access the F9 menu again. When you press F9 now, the menu of the translation will appear instead of the initial options for the object! How can I bring back the initial F9-menu?