I really dont like the idea. Imagine someone getting access to the database with 100.000s of fingerprints.
This forum is against KYC, except during April fools day, and this suggestion is even more invasive.
You can learn a lot from the comments below and above your post, they keep on explaining that your fingerprints doesn't send to anyone which makes this topic more possible if ever the technology becomes high-tech. Though I also doubt that this can happen in just a year or even 5 years from now but the future will be more good for sure.
See this one with a great explanation about your concern.
Most users are posting the same cons against this without knowing how the technology works.
As I said, the fingerprint is not sent anywhere. And the username or email must be entered too.
Simplifying things: you can think of your fingerprint as the password that encrypts the private key used to sign a message. Only the public key (during registration) and the signed message (during logging in) is sent to the server along with the username or email. The private key and fingerprint is not sent, the same as your wallet password and address private keys are never sent anywhere.
Do check this site if you're interested (and do read it before posting here):
https://webauthn.io/