Biometrics (the use of your own biological data as a key to a lock) sounds cool and awesome.
And it’s a disaster. Why is it a disaster? Because it’s the one password you can’t change. So if it’s hacked, you’re permanently screwed. And to date, they always get hacked, easily.
Tsutomu Matsumoto in particular has been able to defeat many biometrics systems with literally dollars in parts.
At best, this kind of thing would be a secondary or tertiary piece of information. At best.