rsvman2 because the club naturally travels on an arc
Nothing natural in golf imo. We are told over and over just how to swing a club, and it must be a certain way in order to get the most from it. Swings are 'manipulated', for every club.
Which will give a better chance of a straight line stroke......glancing the ball, as an arc will, or having the putter head follow the ball in a straight line?
If the arc is not timed just perfectly the ball will be off line. That is natural, I guess 🤔.
I've done the arc, and used the 'stab'(old school, eyes behind the ball) for years. Straight line is best. For me anyway.
And I never, EVER, have a ball that hops, unless it hit something I missed seeing on the green. Stabbing & arcing will cause jumps. I see it all the time.
Last thing is we should never compare players we know/see/play with/consort with on forums, to Pros. Pros have done this stuff since little kids, and they do it every day. 1000's of balls putted just in a season. Most of us will never putt that many in 10 years..........we do not practice it. Obviously.😉