Hot or cold supply for the dishwasher

25 years ago all the dishwashers I installed were always hot supply. I asked the boss one day and he said that the real expensive washers have two supply inlets, one for the hot to wash and one for the cold to rinse. Now I am thinking that if the dishwasher has to heat the water from a cold only supply that it is using electricity instead of natural gas. Logically you would think it better hot shortening the cycles and saving power. Now realizing that engineers have better ways of doing things. Such as expensive electronic sensors that detect water temperatures. The cycles are probably done all from water temperature so if hot water is used the whole machine is disabled. What is better hot or cold, and do they still make dual inlet machines? What would happen if you piped hot into a cold only dishwasher?