The faster spin in the belt drive Kenpool portable washers were to help the drying in the 120 volt electric dryers with which they were often paired. In this area, they could be added to an apartment by the landlord without costly ducting to the outside for the dryer vent unlike the gas and 240 volt versions of the dryers which were also available. When the DD versions of these machines were made, the spin speed was no longer as fast.
About the little GE washer, I have often wondered how these machines with the little impeller at the bottom of the tub would have worked if the center of the impeller had had a narrow post like a Maytag wringer washer agitator had. I tried to hold a plastic vacuum cleaner wand in the center of the impeller to see if I could stop the balling up of the load, but the powerful swirling of the water and the fabrics always forced the wand out of position.