I think PassKeys are great.

On my MacBook with the latest macOS I still can't use them.

I use Brave and 1Password. Clicking the Use Passkey button typically results in some Chrome Bluetooth permission dialog rather than accessing my PassKeys.

I tried to look into this once or twice with no success.

I suspect macOS is at fault. Apple does not seem to care about getting basic functionality right.

To this day Universal Clipboard between the MacBook and my iPhone does not work half of the time.