My concern would be less control and steering as a previous poster observed versus all the fingers on the front of the grip. There are very few competitors who even put their support index finger around the front of the trigger guard these days. Biggest exception to this is Angus Hobdell of CZ fame. Even though he shoots this way, he tells his students NOT to shoot like him. Not that I know every top USPSA shooter, but I can't think of one who points his finger like you describe.