Not sure what you mean, you just need one account for all of Discord, joining a new server is just one click away. Or do you make a new account for each server? That seems unreasonably hard to keep track of. I guess the search could be better but I've never really had too many problems with it and I've seen far far worse implementations. Such as Rocket Chat which has completely broken search. Literally never returns anything.

But yes chat is chat, you can't compare it to a forum style board because they're not trying to do the same thing. You do typically need both a Discourse and a chat server for any major organization.