I'm not against using a passkey as a single factor, and having fallbacks. It's reasonable if you can reliably attach that key to a physical device, so the device can't be impersonated.

I don't think that we should target MIL-xxx standards for daily use, but my security is comparably important to me as military's missile codes are important to them.

So, I don't want my passkey-based services to have a security theater in the name of convenience. There should be some friction to force a baseline security.