The problem with passkeys is that they’re essentially a halfway house to a password manager, but tied to a specific platform in ways that aren’t obvious to a user at all, and liable to easily leave them unable to access of their accounts.

Agreed, in its current state I wouldn‘t teach someone less technically inclined to solely rely on passkeys saved by the default platform if you plan on using different devices, it just leads to trouble.

If you’re going to teach someone how to deal with all of this, and all the potential pitfalls that might lock them out of your service, you almost might as well teach them how to use a cross-platform password manager

Using a password manager is still the solution. Pick one where your passkeys can be safed and most of the authors problems are solved.

The only thing that remains is how to log in if you are not on a device you own (and don’t have the password manager). The author mentions it: the QR code approach for cross device sign in. I don’t think it’s cumbersome, i think it’s actually a great and foolproof way to sign in. I have yet to find a website which implements it though (Edit: Might be my specific setup‘s fault).

The author of your blog post comes to this conclusion:

So do yourself a favour. Get something like bitwarden or if you like self hosting get vaultwarden. Let it generate your passwords and manage them. If you really want passkeys, put them in a password manager you control. But don’t use a platform controlled passkey store, and be very careful with security keys.

The protocol (CXP) which the article is about, would allow you to export the passkeys from the “platform controlled passkey store” and import them into e.g. Bitwarden. So i would imagine the author being in favor of the protocol.

The lock-in effect of passkeys is something that this protocol aims to solve though. The “only managed by your device” is what keeps us locked in, if there is no solution to export and import it on another device.

The protocol aims to make it easy to import and export passkeys so you can switch to a different provider. This way you won’t be stuck if you create passkeys e.g. on an Apple device and want to switch to e.g. Bitwarden or an offline password manager like KeyPassXC

The specifications are significant for a few reasons. CXP was created for passkeys and is meant to address a longstanding criticism that passkeys could contribute to user lock-in by making it prohibitively difficult for people to move between operating system vendors and types of devices. […] CXP aims to standardize the technical process for securely transferring them between platforms so users are free […].