I'm in a few servers with channels for promotion, but I don't think I've really gotten any readers that way. It's mostly good for building a community with other creators/getting involved with collaborations. I recently made my own server for when I launch my patreon, in case anybody thinks being part of a community I manage is a good perc (I don't know why they would but patreon suggested it), but that would basically be for friends and people who already like my work enough to sign on for my patreon, should any such people exist.