Because we don’t need it. The US banking system for example is fairly archaic. Where I live, paper checks went extinct about 30 years ago. Now with SEPA, bank transfers are cheap (cents), fast (seconds) and easy (IBAN). If our banking system would not be as convenient, I’m pretty sure something like PayPal would have been very popular.

Oh, you will underestand. When, besides your bank, half of the planet will know about your shopping habits.

The device called "Smartphone" is only used to collect every possible detail about your life. The smart thing on a "Smartphone" is that, besides your bank, a lot of other "vendors" have access (not only) to your financial information.