This allows me to connect a ScanSnap scanner has two computers (Mac or PC) and various fast switcher of a computer to another using the button. the computer to which the USB signal is indicated by a red LED. The button is an electronic button, but a push button with restraint that makes "click" when pressed.
in a world where everything could change at will, I would have loved that the USB ports are one on each side, not both at the back, this disturbs the cable management, but hey, it does not allow to take away a star.