Actually, none of that is true anymore... Discord now has a fully fledged forum system.
Those are all permanent topics in the "Echo-s bugs" subforum... Just saying... It's not taking the forum's place, but it has more potential than ever to do so. It actually is good for everything now. lol... If it wasn't for the 25 years of information we have built up here, it would probably go that way.
Ok, that solves exactly one problem with Discord. That however still doesn't change the fact everything that is posted there still happens inside the Discord ecosystem. Content posted there is not indexable by any search engine or something like the Wayback Machine. If anything happens to Discord, or the community gets deleted for whatever reason, that will be the end of it. Everything posted there will be lost forever. It's a completely closed-off ecosystem that nobody who doesn't have/doesn't want a Discord account can access and that is the main problem here I think. If independent forums can clearly exist, I just don't see the need to make yourself rely on a platform that runs on proprietary servers, is closed-off to outsiders and at a constant risk of losing everything that was ever posted on there, because Discord, the company, owns the platform and the servers. Not to mention their policies decide what is free speech and what isn't. They are free to censor or shadowban you if they don't like your opinions, it's the same with Reddit really.
As an independent forum owner, platforms like Discord to me if anything should be considered a threat. A threat to free speech on the internet, a thread to preservation of conversations/information for the future, a thread to the independence about the way people have discussions on the internet.
I can't help but wonder, why are people in this day and age so OBSESSED with completely giving up their independence and blindly handing over control over major aspects of their lives to big corporations? I'd say the way we communicate is a pretty major aspect. It almost seems like people buy into the "you will own (and control) nothing and be happy" thing.