If I think about all of this, wouldn't one of the main issues with the lack of internet connection be faked physical bitcoin bills? If you can not scan a qr code or validate in another way that there is really bitcoin behind it, how would you know that it is not simply a copy or a complete fake. So yes, in theory you could make bitcoin usable for people without internet with this system, but in reality it is actually not possible since you can't verify.
There are many problems in the 3rd world country - one of the main issues is illiteracy and then the access to internet and there is non availability of smartphones to keep a track of the things. So the physical bitcoin won't be successful anytime sooner.