Kawhi learning how to handle and beat double teams finding the open guy is always a great thing.
The issue is how the Spurs play him when he has a favorable matchup or when he's open, what type of plays they call for him, how many times in a game they do it, and how many times he gets the ball when he's open...
Even if he's one of the most efficient post-up players in the league, Pop should help to diversify his offense, set screens for his shots, let him run some PnR with the 2nd unit, just facilitate his offense instead of taking and making tough shots every night.