The design of a UDS makes water unnecessary, it's a wet environment.
I think the design of an offset can benefit from using water on long smokes.
I think Butts and Briskets benefit from water when smoked in an offset.
I think longer smokes benefit from water, keeps the meat moist.
I think short smokes, like high temp. Chicken, don't really need water.
I think smoking times may be a little shorter w/o using water.
I think using water gives a softer 'Bark'...
It's amazing the notions I have sometimes.