This is ultimately a form of slavery though.

A country that is a dictatorship - I can understand why their slaves have to go through this. I fail to see why a true democracy would do this though. There is zero need to be required to have a smartphone; all those transactions work perfectly fine on a desktop computer system too, under Linux. People then may have a second device at home, some card reader and/or a thing such as Yubiko or something like that. IMO not even this should be required, but to mandate an app that would not be permissive under Linux - that is true dictatorship. I am surprised the government of Vietnam went that way.