Really the answer to this question should be obvious... The Pilot has all the Gizmos under his control; Throttle, Brakes, Steering, Control Column, Lights and other electrical and radio items. The Marshaller has two just Ping-Pong bats that he can wave about, they are not connected to the airplane controls in any way.
.

That's right! I'd forgotten about the Gizmos! Now, it all makes sense! Pilots, do assure that the left and right Gizmo circuit breakers are in before taxiing!