They still haven't solved the portability problem, there still is no way to use a Passkey without interacting with a proprietary device or hardware, it's still pretty transparently going to enable vendor lock-in. This technology is harmful.
"But it's early days, portability is coming."
Google/Microsoft have been saying this for ages, and it hasn't happened yet. And there's no effort being made to mandate portability as part of the spec, so even if the companies ever actually get around to allowing cross-ecosystem sharing, there are still going to be implementations that don't support portability. And honestly at this point I feel like it is an "if" not a when because Google and Microsoft and Apple are not talking about this being early days, they are encouraging people to switch over right now. So if you launch a feature and you encourage people to start using it for everyday logins, and it doesn't support cross-ecosystem export/import, then it doesn't seem like that's a priority or a blocking issue.
"But 1Password will support this"
No, 1Password is looking to support cross-device syncing, it's not allowing you to move out of the 1Password ecosystem. It's just tying to the 1Password account instead of the hardware.
"But cross-ecosystem syncing would enable phishing"
We crossed that bridge. If you can sync passkeys between devices (and every major player is going to allow that), then there are phishing risks. iCloud accounts can be hacked. Your 1Password account can be compromised. It's not for the sake of security that Apple allows syncing keys across devices but not to other ecosystems.
"Just use a Yubikey"
That's still proprietary hardware and the recovery process that people advocate for with Yubikeys is ridiculous and unworkable. I'm supposed to have 2 keys that I keep in sync and store in different places. I have enough trouble synchronizing Org-mode files between computers, that is not a feasible way to manage account logins.
I refuse to get excited for or advocate for a technology that at this point is just transparently about vendor lock-in, no matter how many times that advocates say it's not. Every time I look into this I wonder if something has changed, but last I checked FIDO alliance is not looking to standardize portability, they're just leaving it up to individual companies. Well, what that means is that maybe if you're lucky you'll be able to sync keys from Microsoft to Apple and vice-versa. You won't be able to sync those keys to a Linux computer (Chrome's implementation of login doesn't even work on Linux without a hardware key, you literally can't use that computer to log-in without a separate non-Linux device).
We should reject this. Passwords have real problems and a key-based authentication system would be a major improvement. It stinks that it's being run this way. And it stinks that advocates for Passkey are trying to argue that it's Open when there's not a single non-proprietary implementation on the entire market. It honestly feels deceptive to me, I have no trust in the FIDO alliance right now. There's been basically no visible progress on this, and every time the issue gets raised, somebody shows up to say that we just need to wait longer. Well... now it's launching. And surprise, we need to wait longer.