(for some inane reason wikipedia lists the installer size for roger wilco... 768kb, now there's a sensible chuckle.)
Also, they need a hosted server (which most people see as a disadvantage, HN is not the norm here).
Discord just isn't a reddit/forums/wiki competitor, that's not what the product is intended to be, and people continue to insist on forcing it to be one for some reason.
I think that's what they're fishing for with the transition to unique global usernames tho. Hashtag usernames aren't a problem in small community chats... they are a problem if you're planning on making a reddit competitor, usernames really should be globally unique for a public board.
When your users keep trying to shove your product into another niche it doesn't fit... you listen.