For me, the only thing that makes passkeys viable is backing them up in the cloud and automatically syncing them across devices. Otherwise, I do not trust them.
The issue with hard tokens is that there is only one of them. By design, you can't back up a Yubikey's content to a second token. This means that any time you add 2FA to a new account, you must have all of your hard tokens in your possession to enroll them. This means a "one token on your keyring for daily use, one token in a safety deposit box as backup" approach isn't possible.
Yubico did propose a potential solution five years ago[0], but that proposal seems to have gone nowhere. Until something like that gets implemented, FIDO2 (and by extension Passkeys) requires some form software implementation backed by cloud synchronization to actually be usable for the average person.
[0]: https://www.yubico.com/blog/yubico-proposes-webauthn-protoco...
> When you need to signup for a new service on the go, you can add your backup key when you get to it
Requires you to remember doing that each and every time. Incidentally this isn't that different from just grabbing your keys like the parent suggested. Only it introduces a new variable: time delay. A lot can happen in that time and we all know the reality is that even a diligent person is going to slip now and then. It surely isn't a reasonable expectation for an average person.
every few months I swap 2 and 3, and re-enroll any missing (kept track of with a spreadsheet)
quite annoying, offline enrollment would be considerably better
It's absolutely a goal, since a PIN doesn't prevent your security key from loss, theft, or physical destruction.
What if you lose your device? Do you install alternate passkeys in a second device? Do you have to do that for every site and service?
That’s one way to look at it: passkeys are just a more convenient form of authentication compared to passwords. Although in my mind you’re arguably not achieving a whole lot considering the security bottle neck is still the same, being the login to your password manager.
I use physical Yubikeys so I’m a bit out of the loop here, but are there any methods for protecting your root password to your password manager in this scenario?
Many password managers do just that.