the Leslie speaker is for electronic organs. At a relatively low power of 50 watts per, you apparently have some residential home type units.
The motorized spinning horn produces a doppler shift which sounds much like a warble tremelo effect, effectively raising and lowering the radiated fundamental frequency at a rate determined by the foot pedal controller (a part of the organ itself) which controls the motor speed. The Leslie effect is not applied constantly; it is turned on at specified times within a composition according to the musical score.
You may be able to resell them to a musical instrument shop or like minded website. As for any home audio use, I wouldn't know why anyone would want to do that as it seems an unlikely application. However I hardly claim to know everything; I could just be mistaken in ignorance. Might be some fun to play around with for special effects in a home theater setup. However again, I wouldn't think that you would want this effect to be on at all times.