A real-life moderated roundtable forum would allow participants to more easily gauge level of intelligence/education and background, so participants would better be able to choose suitable conversational/debating partners. Easy give-and-take allows for more effective and speedier assessment of interlocutors.
An anonymous forum facilitates greater opportunity to interact with conversational partners from variegated backgrounds and educational levels, supporting increased perspective-taking skills.
Participants in either forum need to be able to either defend positions or bow out gracefully, and not hide under calls for civility when stumped for an answer, ie if you can’t take the heat get out of the kitchen.
Pros and cons to both :).