Well, considering that a whole bunch of people got *killed* by the damn things, it's not quite so silly. Especially when the deaths happened in this country and you realize that Switzerland still bans motor racing to this day over a bunch of people being killed in a different country in *1955* and Germany has a whole bunch of laws because of something that happened in the 1930s and 1940s...
Anyway, the Ebersp?cher made heaters had a nasty habit of either asphyxiating the occupants or setting the car on fire, sometimes both. They were (un)surprisingly complex and broke fairly regularly. US market Beetles could also come with a US made option, a special adaptation of the already existing
Stewart-Warner South Wind heater. This was simpler and more reliable but it had the same issues, only less frequently. Basically there were no truly safe options for gas heater options and people eventually got tired of the things attempting to asphyxiate them with carbon monoxide, gas them with gasoline vapor, spray raw gasoline into the cabin, or simply burst into flames and attempt to burn the vehicle down to the ground. They were banned from cars once coolant and electricity based cabin heaters became safe and effective options. (The South Wind series and competitors continued to be made for several more decades for aircraft and military vehicle applications, where the idea was that they could be regularly overhauled based on hours of use - before any problem could occur due to wear.
Even there they had fire problems, though.)
Even though gasoline heater technology has improved, it is still banned at multiple levels in the US because 1) it would be an unattended fire or engine - which is illegal in many states and 2) it violates Federal air pollution laws for vehicles. Instead, we mostly use electric block heaters and less commonly battery blanket or oil pan heaters in colder climates or on diesels. Diesels being far rarer here and fuel injected cars being able to start in far colder temperatures without block heaters than their predecessors, many vehicles even up north no longer come with block heaters; many don't even offer them as a dealer option any more - the US Ford Focus is only available with a block heater in Alaska, for example. It's standard there but not available even as an option in the rest of the US.
I have heard that Canada has recently made exceptions to their version of the Clean Air Act to allow modern fuel based heaters and that they've started being sold there again, but only for big diesel trucks (larger than pickups).
Since I now have a 'mainstream' motor for my market, I'm considering getting an electric pre-lube system, which is an electric auxiliary oil pump that runs right before you start the motor - this pressurizes the oil system and all but eliminates startup wear.