The Outsiders have always been Batman's team, but he usually needs a field leader to take control when he's off with the Justice League. Nightwing will be leading the Titans, Damian Wayne is in the process of forming his own Teen Titans group, and for all we know, Tim Drake may not even be a superhero anymore. Though he has never been a true member of the Batman Family, Black Lightning and Batman have always had a strong working relationship. Thus, his promotion to team leader makes perfect sense.
Maybe it's because of the success of the Black Lightning television show, or the fact that Katana and Geo-Force are being used elsewhere, but the use of Jefferson Pierce makes sense here. Bringing the team under his control is only right. It allows Black Lightning to take on a certain authority within the DC Universe and once again makes him a prominent figure in the superhero community. It also allows for the re-establishment of the fatherly figure he was in Pre-Flashpoint continuity. If this Outsiders team is bringing in new blood like Duke Thomas and Cassandra Cain, Black Lightning is the perfect choice here.
Judging by the solicitations for upcoming issues of Detective Comics, Black Lightning's fledgling group may have a confrontation with Batman right off the bat. It is said that he will come into possession of the Brainiac Files, which could ultimately result in the Dark Knight becoming everything he hated in Amanda Waller. If Waller can't be trusted with this vast amount of knowledge, can Batman be trusted either?
If the Outsiders must distance themselves from their leader in order to truly bring about change in the DC Universe, then so be it. Under the guidance of Jefferson Pierce they can work in the shadows to do what is right with or without Batman's guidance. They may also be able to keep the DC Universe's entire superhero community honest.