Kinda funny. I'm an American who lives abroad, and Google Hangouts has been my savior.
A couple years ago, Google Voice didn't have a native app, and you had to use apps like Talkatone which had their own servers to route the calls through, but now that voice is integrated into Hangouts, it's all I use to call the states.
Keep in mind, the only reason I can use it is because I signed up for a GV number when I still lived in America. I don't think most people can use Hangouts the same way that I do.