No good work whatever can be perfect, and the demand for perfection is always a sign of a misunderstanding of the ends of art.
—John Ruskin
Everybody knows that there's nothing perfect in this world, yet plenty that is imperfect also happens to be very useful.
Identity management is one of these. Conducted by people to account for people, with human beings on both sides of the equation, perfection is out of the question. Only someone who misunderstands the ends of the art of ID can reject a certain solution because it falls short of perfection.
Is using a name to identify a person perfect?
Some people can't speak. Some people can't hear. Some people can't read. Some can't write. Many people share the same name.
A token?
Tokens are lost, stolen, counterfeited.
Maybe a photo then?
Some people can't see.
Fingerprints, then?
Some people don't have hands, at all.
Iris?
Some people don't have eyes.
People cope with imperfection in all aspects of their lives including identity management. Planning for exceptions to the routine ID management transaction is something all existing ID management systems already do. Biometrically enabled ID management systems are no different.
None of the above ID techniques is perfect yet (especially when combined) they are all useful. In this context, a proper understanding of Ruskin's "ends of art" is Return on Investment, not perfection.
The economic value of something does not lie in its perfection. It lies in its ability to help improve things by a measure exceeding the sum of its costs.
What distinguishes biometric systems from earlier ID management techniques, especially in the development context, is that they are an extremely effective and affordable means of establishing a unique identity for individuals among populations that have not been highly organized in the past.
Low access to education? High illiteracy? Poor birth records? Highly transient populations? Recent wars left high numbers of orphans or displaced people? New democracy? For countries answering "yes" to any of these or other similar questions, biometric systems are about the only economically viable choice for developing the ID infrastructure that people who can already verify their identity take for granted.
Additionally, when compared to the investments made by the powers of the Industrial Age to develop their ID management systems — investments still out of reach for the governments of billions of people — biometrics while cheaper, seem capable of outperforming Industrial Age systems. We know this because existing systems using the best Industrial Age techniques have been audited using biometrics. When the older systems are audited with biometric techniques all sorts of errors and inconsistencies are discovered, errors whose numbers would have been reduced significantly, had biometrics been used in the creation of new profiles in the relevant ID systems.
