Unselfish isn't really the word you're looking for. There are two things at fault here, IMO.
One, it's a fault of the system that doesn't give him enough responsibility on offense. A lot of possessions, Smart is relegated to standing on the corners and wings, waiting for the kick out. Sort of like Rondo in his first year under the big 3. If we had to depend on Smart more, we should be running more post ups for him, or allowing him to operate using multiple screens in the pick and roll.
Second, it's a fault of his shot selection. When Smart gets the ball, he's too willing to settle for the 3. And this shot selection is a product of both the system and his current skill level. He currently doesn't seem to have the speed to blow by people (which is where a Wade or Deron comparison will fall short, despite similar body type), and at the same time, he doesn't have the footwork of someone like Pierce who never needed elite speed.