I think it also shows that Harden doesnt settle for the midrange. If you watch the NBA, lots of "stars" midrange game consist of holding/stopping the ball and making tough shots with defenders in their face. Hardens shot chart shows that he doesnt do that. He's much more likely to go to the hole and take a higher % shot.

Aside from the 3's being better value and points per shot--lots of 3's are also "less defended" than backing down a guy and shooting a fallaway/fadeaway.

3's are many times taken after ball swings that leave the shooter generally more open. Even a guarded 3, where you pull up and you're on balance over a defender is probably a higher %age shot than a off balance 17 footer.