"For instance if your left wrist was actually locked, then the shaft would stay as a continuation of the line of your left forearm like it is at address. But it clearly doesn't as you can see from the still frames. Hence the old saying, "feel ain't real".
I'm talking about the front arm....the front wrist....the right one.
Mordan, grab a golf club, hold it in your front hand, address an imaginary ball...... see the shaft of the club is on a different plane to your forearm. If the handle of the shaft continued on till it hit your body then the shaft would hit your body at about your belly or belt buckle. There's the angle. Freeze your wrist and raise your arm up to your rear shoulder. See how there's an angle between the shaft and your wrist. Notice how the club points straight up or slightly towards the target......while you forearm is pointed the other way.
there's an angle.