I use to cut across the ball this helped me save many many strokes
Bought it for my junior golfers to show them connectedness of shoulders/arms/hands swinging in a triangle with pendulum arc. They love it and ask to use it when we do putting drills!
It definitely gets the point across. I think you could improve the experience if you had an explanation for the numbers on the putter grip. I am making assumptions and feel they are correct about the numbers on the grip, but you should give an exclamation.
The Butter Putter is an excellent tool for smoothing the transition in your putting stroke. It's easy to be patient after spending some time with it!
Quite a few of my friends, who play on the Tour as well, were impressed and intrigued. I took it out and hit a few short putts with it and once I put my putter back into my hands I really did feel a difference!