So, they're probably eliminating any chance of Cassandra showing up as an actual character (and not just a kid cameo) in any non movie, for some small thing that probably won't matter. I mean, they have a Batwoman series coming, that would have been a perfect place to see the actual Cassandra Cain, as opposed to basically wasting her as a kid cameo in a shitty vanity project for Margot Robbie that is already destroying the comic Birds of Prey by stealing its name.
So, now that movie is not just ruining one of my favorite teams, the Birds of Prey, its also wasting one of my top 5 favorite DC characters (and favorite Batgirl by far), and probably preventing her from showing up in anything else for years afterwards.
At this point, DC movies have ruined almost all my favorite DC characters. Heck, if you include the Arrowverse taking a shit on the JSA and ruining the Legion of Superheroes, I'm pretty sure that Power Girl is my only favorite DC hero that hasn't been ruined by any branch of DC's live action garbage (well, plus Wonder Woman, obviously, although WW 1984 is certainly losing a lot of goodwill with its godawful villain casting).