Your bank may be luring you into spending more money
I don't think consumers really understand what's going on here . . . Any internal use [banks] can share with their affiliates or share with other companies under the same corporate control. You can't stop that at all and you can't stop them from using it for other purposes you might not expect.
Imagine your bank sharing details about the purchases you made with your credit or debit card. Think about it, they know exactly what you bought. Now, track your purchases to send very targeted ads your way.