because it provides identity.
because it provides identity.
Being a unique number that is tied to a single individual, it can function as a proxy for identity. This, obviously, assumes you are operating like the average user.
And even then, biometrics can't usually differentiate between twins.
For twins, there is arguably no way for software to demonstrate identity, ever.
Social security? Proves you're holding a card.
Biometrics? Proves you're one of multiple with these exact genetics.
Etc. I literally cannot think of a way to definitively and authoritatively tell twins apart in software.
Although, I wouldn't want to give the public key to google/amazon/facebook/twitter :)
Or simply access that key of yours and use it?
The public/private key only prove you hold the keys, not that you are you.
Not identity, just proves you have access to the keys.