Scenario - You click on an existing button. You copy, then paste to duplicate (hint, Control-D to duplicate an object would be nice). You then double-click the button to rename it’s label and the all text is select - ready to be replaced.
Selecting all text allows you to type the new name right away. With a simple touch of either the right or left arrow key you can be at the begnning or end of the selected text. This would be faster for form design than having to hit multiple delete keystrokes or using the key combination to select all (Control-A) then delete, then type.