Why do some banks allow free transactions if a minimum balance is kept in an account?

Some banks allow free transactions with a minimum balance to incentivize customers to maintain a higher balance, which enhances the bank's liquidity and profitability. By keeping funds in the account, banks can use those deposits for lending and investment purposes. This policy also fosters customer loyalty, as clients may be less likely to switch banks if they can avoid fees by maintaining the required balance. Overall, it creates a win-win situation for both the bank and the customer.