Ha. I see what you mean. All these elements in place JUST to make calls on the cheap right?
And yes, simplifying is my motto too, technology per se normally burns more time than it saves if you like me is a geek that gets sucked into figuring out why and how things work the way they do.
Anyway, with a VPN on you can be physically located in a country (China) but with a direct tunnel to another country (US) so that for all purposes any site you connect to will think you are actually in the US and not China.
If I called the US from China it would be more expensive than if I called the US from the US. In fact calling the US from within the US with Google Voice is free (god knows until when), so that's how I can call the US for free.
The reason to have all this GV setup in Aruba though is so that I don't give my customers an Aruba number PLUS I am able to route different callers to different mailboxes, which is very useful for me right now and which GV does apparently pretty well.
Admittedly I need to do a lot of reading on the topic to clarify some aspects but it's much more about routing and having a soft barrier between me and my phone than anything else.