I'm sorry for you loss, but your amazing idea won't work due to the lack of proper infrastructure in some countries.
It is normal for most of the world to use chip cards, while in USA they still use magnetic stripes and they WANT it.

I had a conversation on 4chan's /g/. They do not see a problem with getting all money stolen because not being cryptographically protected. The bank will give it all back. With non-existent internet in most of USA, chip card payments can last minutes to be accepted, while in Europe it takes seconds. They also rely on credit rather than checking in realtime that payment can be made.

American banks not want to invest in new infrastructure and do not want even chip cards. We are speaking about blockchain here, which needs even more internet! Therefore no-one will want to switch to new and secure technologies in states. Without states, the rest of the world will never move forward and get rid of insecure form of payments.