Video chats with more than 3 people start to suffer from an inability to have multiple conversations at the same time. Physical distance of a couple feet and visual queues like the direction of a speakers face allow that in 3d space. Maybe someone can overcome this in 2d? I haven't seen it yet.

I was on a casual call with ~10 people recently and the way only one person could speak at a time was so unfortunate. Really killed the experience compared to chatting in person.