According to the news, what is it that makes the credit card different from conventional ones?

A credit card that only works when it hears its owner’s voice has been developed by US scientists. Researchers hope that the device, which comes with the built-in voice-recognition chip, and microphone, will be a weapon in the battle against credit card fraud. Even if thieves know a card’s password and personal identification number, they’ll still have to copy the owner’s voice accurately. The trial card was created by scientists at "B-card", in California. The first version is three times as thick as a normal credit card, but researchers believe smaller chips will allow the card to slim down to a more conventional size. The card is apparently the first to put voice-recognition chip, microphone, speaker, and battery into a credit card.