I think the difference is cosmetic. The cart is rotating from the same fixed point in both cases. Also the straight arms turn the cartridge to a tangent at the headpiece anyway so there's no such thing as a straight arm. Years ago there was a great deal of discussion among audiophiles about the damping factor of different materials used in the tone arm, its mass, sympathetic vibrations, tracking ability, etc. I think that by 1980 most manufacturers had solved these problems.