Whats the point of challenging calls if refs can't admit they're wrong

Joe Mazzulla tries to change his call for a challenge to a normal timeout after being told by his assistant coach Amile Jefferson NOT to challengeIt was too lateChallenge was not successful

Mitch Johnson picks up a tech after official fails to recognize his challenge

Mitch Johnson asks for a coach's challenge right in front of the referee James Capers but he doesn't call itInstead he receives a technical foulThe Spurs would have won the challenge as the refs gave the ball to the Thunder after it went out of bounds off Chet Holmgren

JB Bickerstaff decides to challenge the foul call on Paul Reed but it was not successful with replays

Alex Caruso is called for the foul on the Rui jumper Caruso immediately signals to the bench to challenge but the coaching staff decides against it with replays

Turnover on the Cavs late in OT replay appears to show both Schroder and Mobley being fouled but Cavs have no challenges