1. Secondary creator
One of the things that make Luka Doncic so exciting is that he does not always need the ball in his hands to make the magic happen. Doncic is comfortable being a secondary creator on the offensive end. He will allow Smith Jr. or J.J. Barea to run the point and offensive sets. That allows Doncic to work off screens and try to get a little more space from his defender before receiving the ball.
Dennis Smith Jr. struggled mightily with this as a rookie. He was not accustomed to playing off the ball, but Doncic has played professionally since he was 14 years old. Those five years have granted him experiences that other NBA rookies have never felt.
It also allows Dennis Smith Jr. to bring the ball up the floor for Dallas and play his most comfortable position. The Mavs want to share the ball more this season, but DSJ can become less engaged when he is not touching the ball on every possession. Playing Doncic away from the orange works well for both young Dallas building blocks.
Having a player as skilled at playmaking and passing as Doncic as your secondary creator is a significant advantage for the Mavericks too.