The main benefit of the Fitz Grip is that it locks the putter into your left palm, which means your left arm and putter move as one. It can also improve the alignment of your forearms.
These benchmarks are for the best players in the world. For the rest of us, however, they seem encouraging, considering many of these goals feel attainable.
It was the combination of scrapping using an alignment line, and adopting a putter with enhanced alignment features, that landed Scheffler in the sweet spot.
The act of making a putting stroke is a simple art. The basics can make or break you on the green. Get those right, and much of your technique will fall into place.