Looking back on it, this young pro was probably a follower of Henry Cotton for whom training the left hand to strike the ball was a key teaching. I am still amazed at how much easier it is for a right-handed golfer to play with a swing controlled by the left arm. It's a shame so few people teach it nowadays.
Below is a video of John Daly hitting a variety of shortgame shots with his left hand. He's definitely a top hand golfer.