I'm sorry but I mean something completely different from what you linked. I mean that the passkey (Titan, Yubikey etc) can be used as an alternative master password. Either that the key only has to be plugged in or recognized or that it acts with a pin query.
My idea has nothing to do with Linux or Mac support for Yubikeys etc. Passkeys are already supported by Firefox for Windows.
Being required to enter my master password frequently means I can't use a secure master password. This is exactly the right kind of scenario to use a passkey instead.