Mains earthing resistance is required to be below 1 ohm, measured at the earthing rod. The earthing mat here by me is, thanks to MTN putting in a 5m by 5m earth mat with multiple grounding rods, well below this. All bonded to everything metallic, cabling, racking, coax, aircons, satellite dishes, waste piping, mains incoming frame with a 25mm cable with protective grease on each connection. It will probably survive a direct lightning hit, even though it is not designed to do so, more there for static and near misses.
A funny thing is actual lightning earth systems are allowed to be up to 8 ohms. This can make a difference, as the 100kA current will flash over to mains wiring nearby.