Biometric passports supposedly increase the level of passport security by including a digital (cryptographically signed?) copy of the passport, along with the owner's fingerprints. However it seems that such passports are accepted even if the chip fails. Moreover the situation seems common enough that a failed chip doesn't (usually) cause any secondary checks to verify the passport's authenticity.
In that case, what's the point of introducing biometric passports in the first place? Wouldn't it make sense to ban biometric documents where the "electronic" part could not be verified?