I use Firefox as my browser and 1Password as my password manager. On my iPhone, I use 1Password + Firefox.
I look at https://passkeys.directory/ every so often and switch my logins from passwords to passkeys. This has included a lot of my common logins like GitHub, Google, and Microsoft.
There is a lot of confusing terminology. For some reason sites will say "login with Touch ID" or "login with Windows Hello" instead of "login with Passkey".
Aside from that quirk, I love it. 1Password syncs my passkeys between devices. I can use them both on my laptop and my phone. It would be inconvenient if I needed to login to a shared computer e.g. at a library or friend's house, but I don't do that often enough to care (though of course some people do, which is totally valid).