Given that the stacking of spheres is built from a stack of planar layers, wouldn't that mean that the stack is prone to shearing forces, sliding the layers over each other?

Wouldn't a packing that is irregular in all directions be more robust?

In the "bestagons" video, it is explained that the hexagons win because there are no straight lines in the packing, but I'd expect these to correspond to planes in the 3d case.