These are probably made for areas with SWER power lines. SWER is Single Wire, Earth Return. A single high voltage 7-20kV line would feed one side of a transformer and the other would return via a ground stake. This is a rather cheap way of electrical distribution for remote rural areas, as only one wire is used. This type of system has a lot of surges and fluctuations due to long wire runs. Thus bulbs like this are needed to take the voltage surges.

These are quite common in rural hardware stores here in Canada. I believe Philips used to make the same thing under the Royale name.

I know GE at least used to make "Country" lamps too...I wanna say they were more of a Canadian thing though.