If I understand the concept correctly the rotor does not only work as "sail" but also as "air propeller", as you need to input energy through its rotation (that

If I understand the concept correctly the rotor does not only work as "sail" but also as "air propeller", as you need to input energy through its rotation (that gets multiplied by the "sail" effect of the Magnus effect). So that's an apples to oranges comparison, that does not bode well for the kite (as it is "passive", not effecting any compounding of energy).