I have to say that this is really strange.
- There are several different protocols, of which a few are mandatory in the US. Why should VW implement two (or more) protocols, one for the US marked, one for the rest of the world?
- I have a cheap OBD-II Bluetooth dongle which works fine with all Android OBD-II Apps so far. As all protocols are supported (tested during initialization), it seems not to be a problem to implement them into the dongle / app.
Due to the fact that this app / system is so comprehensive, this technical issue sounds more like an excuse. Maybe, they don't want return shipments from foreign countries.
Beneath the pure technical functionality of reading out the data from the car and displaying them nicely, the system offers some non-technical features like an emergency agent who calls you in case of a detected crash etc. This service is not (yet) available outside the US, as it also needs some infrastructure. However, they could still say that this services are only available in the US.
Reading their website about the "why not" and "how it's still possible" reveals that the system reads out the VIN of the car, which only in the US contains some additional technical information. They use this for some purposes and get stuck when it doesn't follow the US scheme. Hence, if you want to try the system with a non-US car, you have to send them your VIN first!
Yet, it's strange. Why do they develop an own OBD-II device supporting just a subset of all protocols, when such devices are available for all protocols for a few bucks on ebay. Even when they added some features, why not starting from something existing?