That would depend on whether the air is being exchanged with outside air, and not just recirculated. The latter would be no worse than zero-to-low airflow. Also in the case of an exchange, it matters which way the air moves. Ideally you'd want use the tendency of warmer/moister air to rise, and pull air out from over guests heads. I assume, but can't tell from the pictures, that the plexiglass ends about a foot or so above head height. If that's the case, moving that air with some large fans, and allowing new air to be pulled in below the walls would be a lot better than nothing.
