Why should for deposit only be written on a check along with the bank account number when it is endorsed?

Writing "for deposit only" on a check along with the bank account number ensures that the funds are securely deposited into the intended account and cannot be cashed or transferred to another party. This endorsement restricts the check's use, providing an extra layer of protection against fraud or unauthorized access. It helps maintain clear records of deposits and reinforces the legitimacy of the transaction.