I'm fairly certain most, if not all, the lights in my area are automatic, however pressing the button rapidly causes the "wait" message to repeat as fast as you press it, which is a good way to pass the time while waiting.

More on topic, I wonder if people who jaywalk don't press buttons, or people who press buttons don't jaywalk? Seems like people who are already not going to jaywalk are more predisposed to button presses, but will not cross against the light even if they don't press the button.