I assume that when you say two types you're ignoring slo-fly props, a third type. The heavier props are to handle the high torque of a engine's power stroke and provide flywheel to keep it going. There is no reason not to use the fuel engine props on electrics, other than some extra weight if it's a low torque motor. On high wattage motors it's best to use the heavier stronger prop.

my $.02
Dave