If I had to pick on 'single' difference between hitting and swinging, I would say 'rotation'.
Right you are, EdZ.
Rotation -- Gyroscopic Action -- is created by both Swinger and Hitter. The difference between the two lies in how this Rotation (of the orbiting Club) is created:
Wow...does that mean the use of Accumulator #4 for a Hitter necessarily mean you're Drag Loading? Exciting stuff
No. The key is in what the Pivot Loads during the Start Down. Hitting, the Pivot Loads the Right Elbow to Drive the Club through Impact. Swinging, the Pivot Loads the Left Wrist to Drag it through.