1.) Defensive versatility
The most obvious reason why Spurs fans should be excited for a tall ball is the defensive potential. With so much size and length, the lineup has the chance to rack up blocks and steals as well as dominate the glass. There also isn't a weak link that can easily be attacked.
Vassell took a step back defensively last season as he took on more of an offensive role but he is known as a good team defender and should be back to his normal self playing in the tall ball lineup. Sochan is arguably the best perimeter defender on the Spurs and could spend time guarding opposing point guards and wings, whomever Pop needs.
That could prove to be particularly effective, with Sochan being able to fight over screens easier than, say, Tre Jones, making it harder for his defensive assignments to gain separation. Even if they do, then they'll have Wembanyama to worry about.
Johnson has shown more aggression on the defensive end thus far, stripping his defender and even providing some rim protection. He might still be the weakest link between him, Vassell, and Sochan, but his size for his height and being more engaged should make him hard to attack.
Wembanyama has already shown that he can cover ground quickly and has the potential to be a generational defensive player. As for Collins, he has shown improvement as a rim deterrent by using verticality to contest shots.
He may not be elite in that regard but his size and length will force the opposing offensive player to shoot over him. Putting all of them together in one lineup should give other teams plenty of problems on the defensive end but it remains to be seen if they'll gel as well on the offensive end. To be determined.