One of the biggest inconsistencies I see with people's putting stroke is their lack of distance control and that can often be attuned to your left wrist. If your left wrist is not working well, you're going to get yourself into difficulty. This is for the right-handed golfer, I apologize.
When you're setting up to the golf ball here, you're make a good address position, we want to try and keep that left wrist relatively flat. Then during your stroke, it needs to stay nice and still and stay exactly where it is, any flicking or hinging or breaking of that wrist, that's going to cause you all sorts of problems with accelerating the club towards the hole or the scooping action of even pulling the club phase over.
Now often when you see golfers change from their standard grip to maybe a reversing grip where the left hand is low or maybe even the sort of claw grips and that sort of thing, the pen holder grips, most of that is designed around keeping that left wrist really firm, so personally when I putt, I putt left hand low. My left hand is below my right and when I putt this way, it stops my hand breaking down. We see pen holder grip. Again, it's designed for the same thing, keeping this nice and firm.
You've got some golfers now anchoring the club to their rear arm and again, it's to stop that left wrist breaking over even though the belly putters, the broom handle putters, it's all to take out any excessive wrist hinge. So if you can be nice and firm, nice and solid with your front wrist when you're putting, you'll find your hole more putt and if they don't go in, they'll finish a lot closer.