This article is two years old, and perhaps discord have improved their accessibility, since this user find it more accessible then matrix. Yes, it's a single usercase, but worth mentioning nonetheless.
I think there are other arguments against Discord that haven't been mentioned: data privacy. I know there was an instance where Discord collected user without their consent, and that is enough for me to avoid the platform.
I much rather use matrix or the horridly old IRC protocol than Discord. Or forums. Or just plain old issues!