Apparently pre-rinsing confuses the dishwasher or something. Not doing it leaves me with residue all over the other dishes though 🤷
Different electrics, so their in-built heaters can (and are built to) operate from the cold water line.
NA dishwashers do have a heating coil, but most are only hooked to the hot water line, so that the wimpy heater doesn't have to do quite as much work or at least doesn't have to work as quickly.