It's not a bad drill. This is the "palmar flexion" of the left wrist, or "turning 12 o'clock on the grip to 9 o'clock" stuff we talk about.
As you can see there, it really exaggerates the shaft lean part.
I don't agree that it's the "body" that squares it back up. It's just rotating the forearms/wrists back to square.
I took my old oversized driver out of my bag and only carry the gx-7 now.
Consistent distance and accuracy time after time have made me excited for golf again, it even made my beer taste better.
I am also ordering the fairway woods this week to give them a go with the hope of the same improvement.