That would work for asking, but it wouldn’t help if you wanted to discuss community specific things. For instance if I wanted to discuss the new Heroic lineup after Stabby imploded the previous core I can’t just post this into gaming. People are going to look at it, think “what the fuck did I just read?” and ignore it. That post requires a CS2 community and that community doesn’t exist yet. There have been attempts but it’s never taken off.
I think such communities are important for growth because those are the communities of you stick around for. I probably wouldn’t be on Lemmy if the Formula 1 community wasn’t active here. General communities are great for a general news feed, but the “niche” communities are the glue that keep people together.
You think the gaming community doesn’t have CS gamers?
See my other comment where I do just what you say you can’t:
For example I wanted to know about HaikuOS. It’s an open source OS. There’s no community for it but I know Linux users are the most likely to know about it and the Linux community is huge.
So I asked in c/Linux and found users of the OS.
If I didn’t get a response I’d ask in c/AskLemmy
I’ve done the same with anime and games.