The advantage of passkeys is that no one can trick you into giving your passkeys to the wrong person. Every time this comes up, people say "I don't need that! I've got a password manager. I'm too smart to get tricked." But they are wrong.
The possibility that sites will require attested keys does seem pretty remote at the moment, but if passkeys take off and >95% of people use keys tied to their phone, I could totally see sites starting to prevent you using a key from Bitwarden. I don't think there's a conspiracy trying to achieve this, but the incentives of security & lock-in could push us there.
You won't be able to use your google account passkey to log into the perfect clone of "gmail.com" where the 'a' is actually a greek or cyrillic letter or something, and neither will your ageing parents. You could still paste your password into the fake site from your password manager, or the spyware on your computer could still sniff it from your clipboard.
I'm somewhat desensitized to this myself for non-bank use cases. It's unfortunately necessary with corporate merges and rebrands. After all, how is my password manager supposed to know that it's safe to fill my hulu.com password on disneyplus.com? The same applies to mobile apps providing some-outsourcing-vendor.com instead of my-actual-service-provider.com etc.
For passkeys, there's native support for that type of thing using "related origin requests": https://web.dev/articles/webauthn-related-origin-requests
Yes. That is a feature, not a bug.
Transferability and delegation of authority are features. Calling them "phishing vectors" only makes them seem like a bug.
Being able to give your Hulu or Bank of America password to your spouse is a feature, but giving it to a scammer is a bug.
Can't have one without the other, but I disagree making credentials non-transferrable is the right choice.
You're spreading nothing more than FUD. This is a completely imaginary threat vector that doesn't exist. And even threats that do exist don't always justfity security at every cost. The optimum amount of security is never 100%.
Hopefully after thoroughly checking the URL but you only have two minutes before the Uber gets here and just need to get this one last thing done ASAP...