The number of panels on a footbag influence the shape of the footbag and the way the footbag sits and plays. More panels creates more of a spherical shape and helps the footbag retain this shape during play. The fill level of the footbag also influences the shape.
Less panels can be beneficial as there is less stitching, which means less stress on the footbag. This can also influence pop and stall levels, allowing for an easier time stalling.