Some teams benefit more from immediate responses than "flow state". If you're running a operation where there's lots of small features and design niggles, brainstorming them out with the rest of the team might be better than achieving perfect zanshin, but still having no idea, or doing 8 hours of back-and-forth intense coding then finding out that there's a standard library function or better algorithm that your co-worker could have told you hours ago.
Granted, this would mostly apply to teams who are either very newbie-heavy or work on very small feature increments at a time - or both. And maybe some designers, but I'm not qualified to talk about that. For most other purposes, more isolated environments with a good tech solution for communication would be preferable (IRC, Basecamp, Jabbber etc.)