IIUC there is no point to trying to find a USB *THREE* port for a mouse or keyboard, right? USB TWO is plenty. Because so little data is transmitted.
What about a camera?
I know it uses a lot more, but even at the highest reolution, is it more than USB2 can easily transmit?
What about a camera whose video will never be showing on a anything bigger than a 20 or 24" monitor?
BTW, just for curiosity, do they sell at consumer prices a camera good enough to show a picture on a movie theatre screen. maybe 10 feet high by 30 feet wide. Would that be helped by USB3?