The change, announced on Monday, is intended to streamline the checkout process. Signing a receipt was intended as an anti-fraud measure, but its effectiveness is increasingly debated.

“Signatures pose obvious problems: People often pay little attention when scrawling them, and they can be forged,” MarketWatch reported. “And they’re not even used to prove the person presenting a card is actually the one whose name appears on the plastic.” (Though they are useful when a customer is contesting a purchase, and banks and merchants can look at the signature after the fact.)

Also, with the adoption of EMV chip technology, some credit card companies require a personal identification number and not a signature (which is found in Europe more than the U.S.).

In terms of security, American Express executive vice president Jaromir Divilek explained that the company’s “fraud capabilities have advanced so that signatures are no longer necessary to fight fraud.” The company’s press release also touted, “advanced machine learning algorithms that allow for more precise detection of fraud while minimizing disruption of Card Members’ genuine spending.”

There are a few exceptions to the new no signature necessary policy: if the merchant requires it or if a signature is required by law.