<< Butt my One-Point is: How does it “improve accuracy and range?” >>
Same concept as hollow points, the talisman of shooters who believe that magic ammo can make up for ignoring target & sight alignment along with trigger control.
But hey, a willing seller and a willing buyer is what makes for a great free-market system. More power to the entrepreneurs that come up with these things.
How does it “improve accuracy and range?”
It will not improve weapon accuracy or range unless you add a longer barrel to the pistol. It will improve the accuracy of the shooter because shoulder fired is more controlled.
With that said, if the OP or anyone else is interested in legally obtaining or building something like this the best avenue is to visit your local NFA dealer, preferably an SOT (manufacturer), and tell them what you want. They can guide you through the process and help you with the application.