Ya, it's one of those simple design improvements that seem obvious once you see it, but clearly wasn't obvious because it took so long for someone to think of it.
The granny free throw and the belly putter are both better tools, but they are uncool. We can add the torpedo bat to that list.
Belly putting is anchoring to belly? That’s not legal.
It was legal, until bad putters became very good at putting!
TIL. The new version of this is the "armlock putter" where you anchor to your arm instead of to your belly.