For safety. When you apply for a bank card in Thailand, you need to ask for income in order to ensure the safety and legality of the bank card and avoid malicious application for bank card to engage in illegal activities. When you apply for a savings card online, you need to fill in the income, so that the bank can verify the authenticity of the cardholder at work. Bank card refers to a credit payment tool issued by commercial banks (including postal financial institutions) with all or part of the functions of consumer credit, transfer settlement, cash deposit and withdrawal.