As far as Apple devices are concerned, biometric data never leaves the Secure Enclave, so risk of data leak is non-zero, but sufficiently low for everyday life.

As far as Apple devices are concerned, biometric data never leaves the Secure Enclave, so risk of data leak is non-zero, but sufficiently low for everyday life. Compare that to the massive number of people who use password123 as their password for every account across the web, and yes, biometrics are far more secure. :) More secure than a random 30 character string? Probably not. And if you’re targeted by individuals who are sufficiently motivated to steal your biometrics and the physical device, then neither the password nor the biometrics will be enough to protect you.