Storing passwords in a password manager is storing a shared secret where you can only control the security on your end and thus is still vulnerable to theft in a breach, negligence on the part of the party you’ve shared it with, phishing, man in the middle potentially, etc.
Storing a passkey in a password manager on the other hand is storing an unshared secret that nobody but you has access to, doesn’t leave your device during use, is highly phishing resistant, can’t be mishandled by the sites you use it to connect to etc.
Can you elaborate a bit more? If I create a passkey on https://passkeys.io on my Mac, then store the passkey in a password manager like Bitwarden, I can log into that site on my phone. I was kinda under the impression that Bitwarden stored the private key on their servers, so if their site gets hacked, then the attacker has access to my passkey.io account?
Your vault is encrypted on your device before it’s sent to Bitwarden’s servers, so even they don’t have access to your passwords and passkeys.
More info on how it is encrypted is here:
https://bitwarden.com/help/what-encryption-is-used/
Pretty much every password manager works like this. Having access to your data would be a liability for them.
