As a child, our home had a big, stone sink, massive thing which would have taken many gallons to fill and in which, as babies, we were bathed. Mum also did a certain amount of laundry in it as well.
So for hygiene sake. Mum used a small enamel washing up bowl for our dishes, then graduated to plastic and when I grew up, I followed suit.
It saves water if you are paying by the gallon; it keeps the water hotter longer; you can discard and renew the soapy water if the pots are messy.
It's far better for delicate ceramics and glasses or even clear Pyrex dishes which look very shabby after regular pounding in the dishwasher.
It is ecological better - and yes, I know plastic is supposed to be the enemy these days but I am informed that the chemicals we use in a dishwasher, plus the energy needed to heat the water hot enough for such a device to be effective, several times a week, and the huge amount of water wasted used by these mechanical devices, far outweighs the footprint of a small plastic bowl.