Correct. The spec is about making it easier and more secure to export your passwords and passkeys when you move from one password manager to another. People are misunderstanding this as some sort of federated authentication system to share your credentials between multiple password managers at the same time, which it is not.
Ah. If we’re talking mobile, all bets are off. FIDO prompts require Apple and Google to provide the necessary APIs for third-party devs to use, and are still somewhat new. It’s likely that since iOS browsers are still just re-skinned WebKit (until the EU stuff settles and Mozilla implements Gecko on iOS), FF on iOS can leverage the OS APIs, but making it work with Gecko on Android requires more work.
I was referring to desktop, where those limitations aren’t a hindrance.