Its main draw isn't explicitly gaming, but where your social interactions more often align with that of a friend group / in a group chat dynamic where everyone's talking with everyone or hangs out together at similar times. Gaming is just how it started, because nearly all gaming groups have this sort of social dynamic. (Obviously Discord does support DMs)

The fact that it also scales up to handle hundreds or thousands of concurrent users made it work for pretty much everyone. Suddenly you had one place you could go where there were thousands of other people all interested in the same thing you were interested in, and could meet new people or new friend groups over that said shared interest.

It also absolutely needed:

- persistent, non-disappearing text chats that last forever*

- Free image uploads (and thus meme sharing)

- voice chat & screen sharing, proxied (so no DDOS attacks after a malicious person grabs your IP in a public voice chat)

- role-based access control, so you could have an announcements chat for your server where only admins can say things, you can appoint certain people as moderators, etc

- a mobile app with push notifications (to mimic the text message paradigm of being always available to chat with your friends)

- Discord building out the ability to connect custom bots so early

*: No word yet on if they'll ever start cleaning up old messages and attachments. There must be hundreds of petabytes of attachments stored in multi-AZ google cloud buckets that will never be accessed ever again.