This is something a lot of forums and more private/restricted communities had years ago. It creates a barrier, and if some specific community wants to activate that - sure. But for most instances and communities it’s not relevant.

This is very good from an admin or moderators perspective.

It makes it harder for new people to get into the fediverse, though. I’d love a version of this that helps new users find the right community.

It would be interesting if something like this federated out to other communities. I’d provide info about me as I feel comfortable, and what I want out of an instance of that federated service. Any community that signed up for it would get a notice of my interest and they could ask for more info or accept or deny me. Instead of the one response I could have many options at the end of it.

It would help me find smaller more closed instances without having to know about them, but still leave the control over whether they want to get to know me in their admin’s hands.