The WT is still riding the interest that still exists in "America" in less developed countries.
These people find it intriguing when English-speaking Americans come to their door.
Many assume these people are wealthy. Some are. So you can see the underlying appeal to an impoverished household in a poorer nation.
It brings in huge field service stats. The WT brags about these stats of course. The number that stick and actually get baptised are far far far less than the number that study.
But hey...bored dubs get to do something way cooler than marching around empty suburban neighborhoods in the US, the natives get an interesting experience with crazy, clean-cut, possibly wealthy, Americans visiting them and teaching them English and American customs, and the WT gets to keep people busy and get glowing reports of activity and interest!
win win win
The whole thing works with Canadians and others from English speaking countries as well.
-TE