A direct hit on my home by lightning is very, very unlikely. However, many lightning strikes that hit Earth nearby are by far the main hazard for ham radio gear (in my opinion, after 60 years in the hobby). The huge electromagnetic pulse generated by such nearby strikes spreads in all directions at the speed of light.
I have been taught that such EMP will induce voltage on antenna wires, power lines, guy lines, etc—anything that can serve as an "antenna" for the pulse will have a voltage induced, sometimes very substantial. Here's the question: Doesn't such an EMP impose a voltage spike on both the braid of a coax feed line as well as on its center conductor? And, if so, how does a gas-discharge tube protection gadget on the center conductor of coax provide any safety at all? I am thinking that the old-fashioned idea of just "disconnect the coax and throw it out the window" still has appeal.