Biometric systems---surfacing during the latter half of the 20th century---really haven't become common place until the early 21st century. They are now available for many uses, including security purposes, as well as employee management. There are many advantages to biometric systems, as well as a few notable disadvantages as well.
Security
Biometric fingerprint readers offer a way to capture an identity point that is very difficult to fake---making the technology extremely secure.
Management
Fingerprint recognition software is extremely useful for employers that don't want to use traditional time-sheets. By using biometrics, record-keeping can be done electronically.
Costly
Biometric systems can be costly to implement, which might exclude many companies or organisations from implementing it.
Time
Since fingerprint recognition software only reads one section of a person's finger---it is prone to error. Manually repositioning fingers to get the right reading can be time-consuming.
False Readings
Biometric systems---especially lower cost systems---are prone to errors, including failing to identify an authorised person and incorrectly identifying unauthorised people.