I primarily use Discord as a one stop shop to play and run dnd campaigns. I first hopped on it around 2017, and its was way better than any other group chat app. Around the pandemic all my groups started playing on it and it became relatively seamless. I joined exactly one streamers discord but that is totally it. In general I wouldn't expect it to be a good archive, or forum, nor do I expect it to be secure. I use armchord on PC. I started using it before it was enshittified. For what it does, it does it pretty well.

For the record, I have used matrix and Signal. I think both have the issue that a critical mass of my friends don't use them. I liked Signal a lot when it had SMS support. I used it as a my primary SMS app, and some of my friends had signal as well, so that was cool. now its more like a specialized messenger app, and I fucking hate having yet another one of those on my phone. Matrix encryption keys are giant stumbling blocks to my friends who do give a fuck. I play ttrpgs with some people who could not give a fuck. I would have to set up the server, set up the account, and then I would have have to do the encryption key for them. And like people say, Matrix logs you out every little while. You can turn notifications off and totally forget about it. For my non techy friends, this is literally a bridge too far.

I literally have two friends who think Matrix is cool. No one else even has an account, much less a server. And the support to meet people who have this app is very limited. Cool, but I think it will always be a niche.