Given Smart hasn't shown the ability to be an outside shooter in either college or the pros, he really isn't a SG. He's gotta be a PG otherwise, his future in the NBA is that of defensive oriented combo guard off the bench, which isn't what you want as a #6 pick in a supposed super deep draft.
He needs to come off the bench and develop slowly but he has to do it at PG. He just isn't a SG.