Dishwasher is regularly recirculating dirty, greasy water before rinsing. In order to save water, it just cycles the water with all the dirt through the dishes again, many times over. And only then rinses with a pure one.
I know how dishwasher works. I mean I don’t see why I wouldn’t want to look at that. It is interesting regardless.
Most people prefer ignorance to seeing their flatware get sprayed with filthy water. They’d say “eww that’s disgusting” and hand wash everything from now on.
It’s because of this recirculation that dishwashers consume significantly less water than hand washing.
But people use same water when handwashing too. One sinkful of soapy water first where you wash them, then a sinkful of clean water for rinsing and put them in the drying rack to dry. I believe the significantly is a debatable.