If you put two electric autopilots on a sailboat, and one burns out due to being overworked in big waves/wind, then when you replace it number two will burn out just as fast. Plus, if you lose electrical power (they eat a LOT of juice!) then you have no steering, even if you have ten spare electrical autopilots.
A good windvane will work for weeks and weeks with no draw of electrical current. And the more wind, the better they work. My Sailomat works from gales to drifters, on flat water and in big waves. And my 48’ steel boat weighs triple what Wild Eyes weighs.
Thank you for the explanation! :-)