he's good at spotting up, but he often shoots coming off screens both on and off the ball. he's not strictly a spot up shooter.
When teams collapse when Lebron or Wade drives, the Heat spread out real well, and normally have Miller/Jones/Chalmers/House camped on the 3 point line. Not many teams have that many 3 point shooters, who will get so many open looks. due to the Wade, Lebron factor. Also, on fast breaks, teams are so pre occupied on Wade and James, it always leaves a 3 point shooter open. Also, James Jones leads the Heat in charges taken, he is a underrated defender.