PLANE JIM,

In theory you are absolutely correct, but how many times have you had a servo connection fail? It's never happened to me , but I have had problems with torque rods wallowing out their holes in ailerons, and I've even had one break through the top of an aileron once (crappy soft balsa). That being said, I prefer one servo per aileron but if an ARF has torque rods installed I usually use them.