Hinge Motion refers to the posssible Clubface Motions through Impact -- Close and Layback (or their simultaneous combination).

Hinge Action refers to the Flat Left Wrist producing that Motion by remaining Vertical to one of the three Basic Planes, i.e., Horizontal, Vertical or Angled.

Indeed, Clubface Hinge Motion duplicates Left Wrist Hinge Action. And vice versa.

But always...

Action is cause.

Motion is result.

This distinction is also important when considering the differing Rhythm of the three Hinge Actions, i.e., the In-Line motion of the #3 Accumulator (Left Arm and Club) and the resultant Clubhead Travel distance to the end of the Both-Arms-Straight Follow-Through.