Public forums serve a different purpose to a live chat. Actually what I'm seeing a lot in the comments is people making assumptions about what the purpose of the discord server is, and from those assumptions then conclude that it would be easy to use something else. Some assume that they use it for documentation (???), some assume it's for technical support. But usually what I see, is that these kinds of servers are just an attempt to build a community. And for building a community in the tech space, discord has by far the biggest user base for a chat solution (unless you really think there are more target audience using Facebook messenger, than discord?)