Don’t worry about this. I also apply for a credit card. When a customer wants to apply for multiple credit cards, I also ask the customer to write one first and sign the rest directly. This is just to save the customer trouble. Save your own time and go to other places to apply for cards.
As for why each of us has documents from multiple banks, it is because we also want to share resources. You can help colleagues from other banks to do it, and others can do it for them. I'll naturally help you with it. It also increases your card acceptance rate.
Our industry also has industry ethics and will not fill in your information randomly. If you are caught counterfeiting or stealing a customer's credit card, the fine will be heavy. The minimum fine is 3,000, and serious cases include imprisonment.