Batman is one of the few superheroes who sometimes actually works better as a side character (look no further than the classic Justice League cartoon for evidence of that), so keeping Ben Affleck in the wings could be a smart move while establishing the more obscure heroes and villains in more central roles.
That point becomes even more noteworthy when we consider the fact that Ben Affleck’s Batman can still appear in all of the aforementioned films.
It’s arguably even more well-connected than the Marvel Cinematic Universe was at this point.
Between his cameo in Suicide Squad and his rumored role in Diana Prince’s solo adventure this summer, the DCEU has proven that (for all of its faults) it knows how to stay interconnected and weave characters in and out of each others’ films.