I've been working on the game for years and used to have a pretty big community that I only communicated with through the in-game chat. Then life got in the way and the server was down for two years which meant I lost most players (I don't require an email address so no idea who they are). I really wish I had set up the Discord much earlier so I could at least have kept a communication channel for the early adopters.

All in all the Discord server has been a major turning point in community building so I recommend setting it up and promoting it as soon as possible. I've even added a quest for new players to join the Discord server that gives some in-game rewards.