What's the point of biometric passports if they're accepted even if the chip fails?

Question

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?

Answer 1

The point of introducing biometric passports is that they're much harder to forge for common criminals. For example, one could replace a passport photo to another person (this is still possible on certain passports), and use this passport for a different persona. With a biometric passport this is not possible, because the photo is also stored in the chip, and they won't match. And if someone replaces a chip as well, then the rest of the information won't match (actually the chip won't read in this case).

Thus most people will have an extra layer of verification, and those with a damaged chip would be subject to extra scrutiny.