I'm a SLF working as an Internet security consultant. Biometrics are useful in two areas:
1. Verification - in which you identify yourself as "John Smith" and then the biometric matches your physical characteristics against a database. Iris scanning is the front runner for this technology (cheap, quick and accurate) and is currently under trial in several airports in Europe and the U.S. Finger/hand recognition faces some consumer resistance in that people are nervous of having their fingerprints on a central database (even though the technology does not check actual fingerprints, only a few of their distinguishing charcteristics).
2. Identification - in which the biometric system scans everyone looking for known bad guys. Face recognition is an obvious technology for this purpose since most lounges will already have CCTV surveillance systems. This technology is rapidly improving, but still prone to false positives.
Hope this helps.