While the chip data, in the mandatory data groups 1 and 2 (Machine Readable Zone and facial image), does confirm the printed data, the chip can contain more optional data, including additional fingerprint and iris biometrics. As well, the chip data is secured by the PKI (Public Key Infrastructure) which is an additional strong security feature.
The chip data can also assist border officials in other ways. For example, the facial image stored in the chip is a higher resolution version of the printed photo, so when displayed on the border official's screen can mean a more confident match with the person.
Courtesy the Keesing Journal, 2009