Do you truly not understand why a developer creating a location-based discovery app - an app that will be judged mostly on the quality its location-based content - might need to launch in limited locations to start? Does this really need to be explained to you?
If the problem is that Google Play won't let you download an app from the U.S. store based on where your current ISP is located then: 1) that's dumb* and 2) download Field Trip when you get back to the U.S.
The point is developers shouldn't have to worry about people in un-supported countries downloading their apps and finding them worthless due to no content.
* (it should be based on your Google Play account settings or billing information)
Except when you have a really really good reason to do so, you shouldn't limit your app download countries.
Even for apps requiring physical or legal presence in the country (specific store app, subway guide, bank etc), you still have a chance that the people using it set their Google Play account to another country or use foreign billing information. Expats and tourists are an obvious case, using the billing information of family or friends abroad is another one.
Setting multiple account in different store countries is a major PITA, and getting updates for apps downloaded on mostly unused stores is painful as well.
The other side of this coin, people downloading the app to use in their home countries when those countries are un-supported, is much more common. Probably two orders of magnitude more common. Sorry it sucks for you, but I'd make the exact same decision as Google here 100% of the time.
Would be nice to have a third option, that incorporates the country limitations into the purchasing process and warns you when buying the app that it has no data/support/whatever for your country. At least then those of us who do travel frequently and want to be able to use these apps when we do will have that option.
Hans the German downloads the app. But as he walks through the streets of Munich, the app doesn't show him anything interesting. Hans posts a 1 star review on Google Play, saying "app is broken does not work on <whatever phone>". This is not desirable for Google.
I think you missed the point, let me go get it for you:
It's a location based application. Operative and key words there are "location" and "based". It makes more sense to release in a limited location you have proximity to and are familiar with in an early release to iron out all the bugs before making an international release where tracking down inaccuracies can be much more difficult logistically.
I doubt it's an arbitrary restriction, it's done for the sake of ensuring the app works as designed in a controlled test-environment.
I'm sure I'll enjoy it in a few years.