Not really into the webtoon stuff but I can see the merit with starting with Batman and branching out into other stuff
A lot of the fans on this site and the internet have a Batman complex that clouds their good judgement you don't launch a new endeavor like this and use characters with limited to no viable fanbase not to start it out that would kill the momentum of the move

Thankfully DC doesn't listen to the angry fans too often this is a another good example of fans being wrong about something