Fan discords are just a cringe sideshow for big corpos, but for small corpos and indies they are AIDS infested cancer 1000% of the time. The worst, most annoying, likely schizo members of a community naturally gravitate towards it, and it acts like a hugbox circlejerk that normalizes and encourages their annoying and schizo behavior, to a point that it will actually take over entire streams. These people also often happen to be the bulk of the paypigs, so it becomes basically impossible to do anything about them. Then inevitably some petty fight happens, and then whatever general /here/ becomes a constant dumping ground for discordfags trying to namefag and gossip about each other.
God fucking forbid if the pertinent vtuber(s) interact with it too, which is when you get hardcore toxic clique-ification of the fanbase, and a real push into groomer tier antics that A L W A Y S blows up into an embarrassing mess of schizophrenia, cuckposting, and drama, that inevitably births antis and chases away the fans that aren't annoying schizo wannabe groomers.
I have experienced this all firsthand multiple times now, and it's at a point where I've sworn to myself to never get involved with another vtuber that embraces discord, or a corpo that lets them do so. It is my sincere wish that anybody reading this considers doing the same, because it will save you so much grief.