If something like this really can be accurate, I would think it would need more data than 1 year.
Harden and George were both much more efficient players than Smart at a higher usage rate even early in their careers, and on the other side, Harden had a similar steal rate to Smart IMO for a completely different reason (Harden had very good defensive players playing with him and he could hide and roam whereas Smart got a lot of steals by making plays on his own).
Harden wasn't greatly efficient in his rookie year. He was pretty good, but he was terrible at finishing at the rim. Harden's efficiency in his rookie year was supported more by having Westbrook and Durant on the roster than anything. He was able to spot up and shoot a bunch of 3s, which up'd his efficiency. Any time he tried creating on his own, it usually ended up in failure (47% FG at the rim). Smart didn't really have that luxury his rookie year unfortunately.
Anywho, I've always touted Harden as a good comparison for Smart not because I think Smart can be an ultra 25 PPG player, but because I think they have similar offensive tendencies. Both have always ignored the mid-range game in favor of taking almost all of their shots at the rim or 3PT line. Both have a knack for drawing fouls and getting the ref to call whistles for them. Neither are incredibly explosive, and it took Harden a year to figure out how to finish at the rim and adjust to NBA length and speed after being crazy good at it in college (sounds familiar to me..the question is whether Smart can figure it out or not like Harden did). I don't think Smart will ever develop that kind of knack for scoring, but I do think he could learn a thing or two from watching some Harden tape considering they seem to be in similar athletic range with one another and have similar tendencies on offense.