It is when he is on the break and his overall physicality. However, he is much more of a face the basket player than Barkley. Barkley played the post game a LOT. Zion would too probably, but that is not where the NBA is today.
Honestly, there is a lot of LeBron in Zion's game. Athleticism, speed, overall size, skill set. It is all very similar to LeBron when he came into the league. LeBron added the shooting after he came in. The thing that makes Zion so intriguing is that he has all the athleticism, skill, and size, plus he has a non-stop motor AND he is an excellent defensive player.