I used to be a fan, unless I was doing something wrong on the website, you can only log in with proprietary software like github. You used to be able to just create a room. I realize that presents its own problems, but email should be an option.
Communication platforms are going to be abused by organised crime, pedofiles and all kinds of unsavoury people. KYC rules mean that if a platform finds that kind of content, they can report it to the appropriate authorities.
I dont know whether its by a law, or something else, but even if you self host its a good idea to know who your users are and what they are doing.