Psh. You do you. If you aren't a discord person, no worries. It just means all interactions will be through the forum.
I can't speak for anyone else, but I know for myself I really do not have time to go investigating other people's lives. So if there is a way to track what other servers someone is on through discord ... I do not know it. And even if I did I don't have time/energy/interest in that level of snoop.
I will say some of the group are pretty open with their lives on the discord server itself. But it's up to each person. *shrug*