In the sense of being a wiki, it allows collaborative editing of its content and structure by its users.
But that's simple and understandable if the information being edited is true pure facts...
There is no problem when a game wiki is being edited, but when it comes to chat rooms...
As you know, a chat room wiki has a sensitive critical part (Who is a regular? What will be their description? Is this one still a regular or put them in previous ones? And so on), the context of which depends on the main editor of the wiki. Opinions and feelings strike hard in that part. That's why we expect the main editor to be someone reasonable and professional, chosen wisely by the room population.
Here, we reach a conflict between the core of a wiki (everyone edits) and common sense... When that sensitive part is being edited by someone rather than the main editor or a registered member who is part of that wiki, when an unknown wiki contributor starts editing that part, it becomes foggy. We don't know if this was vandalizing or a true harmless edit.
The same goes for the talk page of users and wikis.
Personally, I have encountered some edits made by contributors, mostly vandalizing and some not. But even the some is doubted... We can't know for sure that the edit is true.
So... It would be better if chat room wiki and talk pages are edited by registered members only. Thanks for contribution, but sorry.