HI Tom, Just thinking about it off the top of my head, I think it has at 2 reasons, an increase in surface and contact area, like a multi-plate clutch, motorcycles use these types today and many of them have a "wet" clutch for wear and cooling purposes. Also allows a smaller flywheel and less mass to accelerate and decelerate.
Two, the mass and weight can be kept down, for accelerating purposes, and flywheel effect, when putting large amounts of power to the transmission, to the differential and finally to wheels and the rubber to the road. And then I guess just because they can.
YIA... Paul