I believe I seen a Babolat video that said it relieves the pressure on the gripper. Can't understand that but who am i to argue. I can see how it keeps a constant angle on the string going into the gripper so you will not damage the string when pulling tension. That is why Herb added the diablo to the Wise as an after thought.
I have the ability to drive people crazy, not sure if I was born with it or I learned it but I'm damn good at it.