>The extra code might there to determine your spending habits across other apps and your bank balance and then to determine where you're located so that it can provide information on regional affluence so they can price toothpaste & brushes higher in strategic regions...

1. I highly doubt that's done on device

2. how are they supposed to link you to your bank account? AFAIK cross app tracking is opt in, at least on iOS so unless the user explicitly opts in, you're not going to get a cross-app identifier.