My inexperienced opinion is that in order to conserve water when doing dishes it makes sense to put soapy water in one sink bowl and clean rinse water in the second bowl. Dirty dishes go into the first bowl for cleaning, dip in the second for rinse, and off to drip dry on the countertop. I'd choose a two-bowl sink.
A person with a single-bowl sink could stack the soapy dishes on the counter until all have been washed, then drain the wash water and re-fill with rinse water, move the dishes off the counter back into the sink, clean up the soapy water mess on the counter, and move the dishes back to the counter again after rinse to drip dry. To me that sounds bothersome, but to each his own!