[yyyyip]

I don't mean using the fingerprint as a key.

I mean that if you can produce a fingerprint image corresponding to a blockchain hash and it matches your fingerprint 20 years later, and this is linked to 20 years worth of blockchain recorded credential information, I would find that very compelling evidence that you are who you say you are.

[dane-pgp]

This idea of having 20 years of linked entries in an append-only distributed log is very powerful, and is the basis for the "idchains" system discussed here:

https://www.youtube.com/watch?v=xZC98s4paYY

It controversially opts to use faces rather than fingerprints, but faces are easier for humans to verify, especially without special hardware.

I don't think the video describes a complete system, but the idea has merit and I wish it had been developed more.

[somenewacc]

Fingerprints change (sometimes radically). Relying on them may make you unable to prove you're yourself.

[jjawssd]

What you described is identical to a key