There are a lot of social issues that a system like this might entail, in addition to privacy:
1. Not everyone has a smartphone.
2. Not everyone has an electronic account with which to pay (or for practical reasons, they can't use it frequently).
And the people that fall into those categories aren't just fringe. Parents give dollar bills to their kids & send them to the store to fetch food. People without established credit might have to use cash for purchases, etc.
Probably - I don't know the procedure. I do know most people consider debit to be a less secure (for the consumer) form of payment than credit or cash though.
1. Not everyone has a smartphone.
2. Not everyone has an electronic account with which to pay (or for practical reasons, they can't use it frequently).
And the people that fall into those categories aren't just fringe. Parents give dollar bills to their kids & send them to the store to fetch food. People without established credit might have to use cash for purchases, etc.