Again, we barely know anything about it. Affleck is probably a cameo in the beginning and end while Keaton plays part of the Thomas Wayne role from the comics. The main story is still about the Flash.

They aren't going full Flashpoint and they certainly aren't doing anything close to an "into the batverse".

Sure, they could have opted for a cookie cutter script where good guy fights bad guy and whatdoyaknow the good guy wins. But they've chosen to do something more interesting, which if it works could have major implications for the future of the brand. This isn't something they've just jumped into, they've been working on a script they like for years.