Yeah, I really don't get why they don't just release them everywhere. The same for all their products btw. In the Netherlands they still sell the old Google Wifi (1st gen), which is apparently their main product as it is the first thing you see when you go to the store site here.
Google: we made release!
Rest of the world: ... In America
Google: awesome profit!
Rest of the world: our market is like 10x the US market
Google: but we made release!
Perhaps because the live translation feature isn’t ready for the locale yet?
I would hazard a guess that the majority of people who can afford these outside the US are already very proficient with both English and their local language(s), and wouldn't care much about this feature.