Even those who like their dishwashers say some stuff has to be rinsed and some stuff has to be washed by hand.
Thus the overall water use for a 'dishwasher user' is what the machine uses plus the amount used by rinsing and hand washing.
It seems to me inevitable the dishwasher household will be using more water to wash up than the household which washes only by hand.
And as has been observed, the hand wash household has the option to use the washing up water on the garden or down the toilet.
Our machine uses 9.5l on its eco cycle
Final sterilizing rinse @63C
I doubt any hand washers match those numbers. 60C is the minimum to sterilize - if you hand wash and do not rinse at high temp you are leaving bacteria on the dishes
No need to pre-rinse - just scrape off the bulky crud