A good center is required to compete in the modern NBA
The evolution of the modern big man has changed the sport of basketball. Nikola Jokic, the Timberwolves' duo of Karl Anthony-Towns and Rudy Gobert, Anthony Davis, and Chet Holmgren are who the Jazz will need to get through in the West, with Kristaps Porzingis and Joel Embiid potentially waiting in the East.
Teams looking to win a championship have to be able to, at minimum, slow down these dominant centers who can stretch the floor, pass, and rim protect. As we saw last year, Daniel Gafford for the Mavericks couldn't do all those things, but he could protect the rim, play pick and roll, and score enough to be an asset.
Kessler has been a jack of all trades, master of none in his first two years in the association. For him to take the next step and be a center who can be part of a winning team, he needs to be known for something, whether he improves his scoring, becomes a monster rebounder, or is a shutdown defender in the paint, he needs to master an aspect of his game. If he bounces back, it's a safe assumption he has done that.