I use a bowl simply because sometimes I need to use the sink for something else (rinsing of salad etc) and it's easier to lift a bowl out rather than two forks, two knives, two cups, two plates etc separately. It also means if something needs soaking, I can lift the bowl out and put it on the side and still use the sink.
I have a dishwasher, but I seem to be the only one in the house capable of loading it, so everyone else puts the dirty stuff in the bowl.