You don't need to sign up for forums for them to be searched through.
The point is that Discord is an information black hole. It's all contained within the server, unindexed, private, hidden, and entirely gone if the server gets deleted.
You would need to sign up to be able to participate, which seems to be the pain point from the beginning. That was the reason why I suggested email threads akin to what Linus and Co use for Kernel development, since those can be searched no problem, whilst almost everyone has email IDs
I don't think participation is the problem. If you think about it, you wouldn't want just anyone to post something on a platform without first engaging in said platform. That can only have a neutral or negative effect. People asking stupid questions or people cursing out users. The act of signup ensures that the would-be poster has to signup first and rationalize their post during that process.
Therefor, the problem must be something else, it is the information gateoff (amongst other things) that makes Discord and similar apps unfavorable for community management and information distribution.
There' plenty of reasons, most of which have to do with the human psyche and error. I imagine it's largely due to convenience. And then one may rationalize that initial thought by assuming that most of their potential audience uses Discord anyway, so they won't consider other options due to just how damn easy to setup and monitor their community via a Discord-like app is. They may not consider searchability, or information access at all. They may give very little weight to the fact that their entire potential community is subject to Discord's whims. They simply may not be aware of how beneficial other options are.
Humans do not act based on reason. They act on a mixture of emotion and intuition, and only reinforce their initial position with reason, of one form on another. There is no point of attempting to apply logic to why the people (generically) do anything because of that. On the other hand, attempting to look at this scenario from why something should be done a certain way, as opposed to why it is done a certain way, has merit, as it allows us to influence a decision before it is made in the instant it is conceived.
The integrations and plugins, established workflows, support systems ticketing it's all turnkey. I hate the platform and I wish people wouldn't use it but I understand the draw.
There are bots that tie in and store tickets several of my software vendors use them. When you have a problem you drop into a certain channel and make a request it issues you a ticket with a link creates a new channel that's just a conversation between you and support. At first it seems clergy but after you use it a couple of times it's reasonably slick
A lot of people have discord, a lot less people have slack.
Slack is also starting to charge for those workflows. My slack bill at work is gone up 50% past what it was. And I'm now getting monthly warnings from using my integrations. They would like me to put a credit card into handle more jira tickets.
You also need to pay to just have message history preserved on slack. Discord that information is there for free for as long as the server/discord exists.
I'm not saying people should use discord, but people are using it because it's free to use.
Because most selfhosters are too lazy or inexperienced to break away from cloud services. Docker is great but it has also enables a "just run this docker" mentality that mirrors the Windows "just run this exe."
edit: I think that the opportunity to learn how a project works, how to debug problems and how to integrate a project into their own setup is obscured.
Because if I didn't use Discord then I would be the only one in the community. Discord has a massive userbase especially with gamers. You give them a Discord link and there's a decent chance you'll see them join and post a message. Give them any other link and they'll never make an account, they probably won't even click the link to see it.
I provide links for Discord, Lemmy, Kbin, Mastodon, Steam group, and GitHub. I see lots of people come in on Discord, but 0 on the others except for myself lol.
Only the few actual contributors use the GitHub, don't think I've ever seen a non-programmer submit a bug report on my GitHub or use the discussions or leave any comments on releases or anything.
I'm also on Moddb and NexusMods, got a few comments on Moddb, none on Nexusmods yet.
I also have Twitch and YouTube of course, I get small numbers of people commenting on those.
Nobody has even asked for any other type of community, Discord is just want they want. If I just wanted to talk to myself then I wouldn't bother creating a community/forum at all.