Not nearly as much protection as he thinks.

Lightning consists of the near-instantaneous transfer of a large electrical charge between (1.) one cloud and another, or (2.) one cloud and ground.

In the latter case, tremendous currents flow through the ground over to the point where the strike occurs.

Buried cables are much better electrical conductors than dirt - which means that when a lightning strike occurs nearby, these cables often carry much more of the current than the surrounding dirt. Anything that happens to be connected to the cables during the strike is likely to be subjected to sudden, huge swings in electrical potential - which can most certainly cause major damage.