The one API I have on discord, likes Discord as a place for casual chat about the system. I think the devs prefer it because it is an active place for the community; to word it better, 'hey look at this cool thing I did' > response within a few minutes 'that's cool' heart^5 fire^3 thumbs up^7. Whereas on a forum you'd be waiting for hours, or just not have that casual of a conversation.

It replaces the old usage of IRC servers.

The help channel is highly responsive, and great for things you want a quick chat about, need a response now, or if you get help now great, but if not, you'll figure it out on your own before you would ever get help on a forum, so it's not worth posting to a forum.

Threads really do help organize when a discussion is going to be large, and discord is very much searchable, just not from your browser search engine.

For changes to the API, ideas, issues, or bugs, they direct you to github "Discussions" or "Issues". They do have an idea discord channel, but it's a more casual thing, or far out there discussions.

Discord does get a lot of hate for it's searchability, which is valid, but I don't have a problem with it as long as places like Stack Overflow (or what replaces it) are still around.