An overflow rinse was helpful in solid tub machines for getting rid of lint and, in the early days of using soap in automatics, of suds and soap curd, a product of soap, hard water and precipitating water conditioners. They were not necessary as GE showed by the mid 50s where an overflowing tub fed a recirculating lint filter and most automatic laundering was done using a synthetic detergent. Mostly they used an inordinate amount of water (almost as much as another deep rinse in some machines) and a single overflow rinse is not as effective as double deep rinses with a spin period after each rinse. Today they are way too wasteful of water for all but demonstration purposes in the hallowed halls of laundry museums and even then, the water should be saved for another use.