 The Act is intended in part to keep the country's financial services operational in the event of a catastrophe that could make rapid long-distance transportation impossible, like the September 11, 2001, attacks.The Check 21 Act makes the digital image of a check legally acceptable for payment purposes, just like a traditional paper check.Before 2004, if someone deposited a check in an account with one bank, the banks would have to physically exchange the paper check to the bank on which the check is drawn before the money would be credited to the account in the deposit bank.