Ken Rosenthal has an article in The Athletic today about how NY has cut down on opposing SBs so far this year (fewest SB attempts/successes so far in MLB, 13 and 7), and this excerpt I think is a good example of what Boone actually contributes.
"Equally unexpected: The coach spearheading the Yankees’ increased emphasis on throwing out baserunners attempting to steal is new third base/outfield coach Luis Rojas, who was part of the
Mets’ organization when that team allowed more stolen bases than any other in 2018 and 2019.
Rojas, 40, helped the Mets improve markedly in controlling the running game in 2020 and 2021, his two seasons as manager. But when the Yankees interviewed him for a coaching position last offseason, guarding against stolen bases was not even a topic of discussion.
The Yankees’ announced Rojas’ hiring on Nov. 15. In December, after the start of the owners’ lockout, he was at Yankee Stadium, meeting with Yankees manager Aaron Boone. Their conversation turned so spirited, the two strolled out to the field and talked through different offensive and defensive plays.
Upon returning inside, Boone and Rojas began speaking with some of the Yankees’ analysts about controlling the running game. Rojas explained that he took on that responsibility with the Mets, who last season ranked 20th in stolen bases allowed — a dramatic improvement from years past.
As Rojas recalled, Boone said, “You want to do it? Let’s go. Go ahead and do it.”"
He is the face of the team who essentially serves as a press secretary, I think most of his actual baseball duties have been delegated to NY's increasingly impressive coaching staff. Your answer to this may be along the lines of "that's what a good CEO does, they delegate", but Boone is far from a CEO.