This is a much needed Trust + Safety feature. For any number of reasons, there are people who want to be part of a community (read messages, PM, etc.) but don’t want to be seen / found in the member directory.
As an admin, I’ve been asked by a user to hide them from the member directory and there’s no way to do it. Unfortunately even if I turn off the enable user directory setting, they still appear in the member list for chat channels.
A simple checkbox in preferences to opt out of being seen in the member directory and chat channel member list (except for by staff/admins) would be greatly appreciated.