"are there any real advantages here"
Raw power output, no. Propane is less powerful by volume than gasoline.
But, if operating at extreme inclinations or tilt of vehicle is encountered in operation (such as off road and rock crawler vehicles) then propane is the fuel of preference because neither the fuel tank nor the fuel system is much affected by the angle or tilt of the vehicle.
With gasoline, you have issues of whether the fuel pump suction port can be kept submerged in the gasoline at extreme angles, and if the delivery to the engine is via carburetor, there are issues of maintaining a useful float operation to meter the gas flow at extreme angles.
Another advantage of propane is its Octane rating. With an Octane rating of 100+, you can utilize a higher compression ratio with less worry of detonation.