If I'm imagining how that is staged, the stage-left part of the audience would not get to see much. The charades would be partially from the rear at best, and likely most of the action would be obscured by the oversized projection display. The middle and stage-right sections of 33 were probably used which still gives for a sizable enough audience and just left those seats adjacent to Johnny's podium empty. (That said, a pickup shot with some audience members filling the seats wouldn't be too much to ask.)
ETA -- Those seats were filled for the series finale. 🤷♂️