What biometrics are
It's a way of verifying you by physical traits like your fingerprint, face or iris. In most cases the biometric data is processed only in a secure area on the device and is never sent to or stored on a server.
In practice, it often works as a convenient way to 'unlock' your password or PIN on your behalf.
Benefits
The strengths of biometrics.
- Fast and easy to enter
- Hard for someone to peek over your shoulder or leak
- A strong second factor when combined with a password or PIN
Limits and cautions
Biometrics have weaknesses too.
- Biometric data can't be changed like a password if it leaks
- Risk of being unlocked while you're asleep or by force
- Recognition can fail depending on injuries or the environment
- A strong PIN or password backup is essential in case the device is lost or errors out
How best to use them
It's safest to keep a strong password or PIN as the primary lock and add biometrics as a convenience layer. For important apps like banking or healthcare, set them to require both biometrics and a separate password.