A large issue I see with this is that of moderation. Discord, Slack, Reddit, and so on, all have appointed moderators for every community that keep users in-check according to community standards. With this idea, there are no 'owners' of any of these chatrooms, so are you going to moderate it centrally? That is a lot of work and requires a lot of people, just think about how much work it is to moderate a single twitch chatroom for spam, let alone an unlimited amount of them.

Would love to hear if you have any ideas on solving that. Besides that, I like the idea.