The note is put in there to probably differentiate between taxi under its own power or being repositioned by a tug. Section (c) explicitly states, "all ground operations involving taxi."

Hey man, its your ticket. If you wanna try it out, go to ORD or LGA and be number 20 for takeoff and every time you move forward, then set the brake, you can start talking about your favorite football team with a Fed in a jumpseat. Then you can show them the note and let me know the reaction.