I just contacted the developer account with the following text. In my mind this has huge potential to help the world find the right level of isolation and potentially leverage powerful adaptive learning algorithms. I don't know why this approach is not getting more mindshare in the current climate:

Is there a way you can enable other countries to also use this app? Even if it means you can't validate the users mobile telephone number (until that country's government negotiates a means to paying for SMS verification), allowing is to install it would allow collection of contacts to start immediately and raise awareness of this game changer.

Personally I would allow users to opt in to pushing the collected data online as that allows far more powerful analysis and the ability to continue to refine the algorithms to infer level of risk based on multiple "hops" of contact in the preceding days. For example carrier X overlaps with Y on day 1, then Y overlaps with Z on day 2. As soon as X is diagnosed Y gets a high risk rating and Z gets a moderate one. The exact criteria can evolve as we learn more and the data can be used to help train the model. The more people use it, the better it will be for everyone.

If you want me to help I can, but either way you could save millions of lives with this app if it is adopted globally.