> They bind you to your device/iCloud/Gaia account

Then don't use Apple's/Google's/whatever Gaia is as your passkey provider?

> Mom can't figure out what they are or how to use them.

Then do something nice for your mom and set her up with Bitwarden, 1Password or KeepassXC, which prevents the platform lock-in.

> It's one further step down the attested hardware software and eyeballs path.

None of the synchronized passkey implementations, which big tech has been pushing lately, support attestation, so this is just FUD.

Yubikeys do, but fortunately they don't seem to have the (non-enterprise) weight to make it mandatory for all passkeys.