> they would have used something like the size of Germany for a European, or "twice the size of South Korea" or something

I don't have a concrete proof, just a gut feeling, but I think that this kind of comparisons are much more common in texts written by Americans and for Americans than in any other culture, that's why:

> There's a meme about "Americans will use anything but the metric system" when describing buildings as "100 school buses back to back" or "3 football fields"