I try to use passkeys when possible as I'm also a 1Password user, but this hardly "just works". Firefox on Windows often triggers the Windows password manager for passkeys (some how this is only on some sites), making it impossible to use 1Password.
I've seen the same on Android too, and I think there's a difference in how Chrome and Firefox are handling the requests.
Then you get in to cases like a Microsoft Account. You need to use your account to log in to the device that has the passkeys, so the workflow never works properly and you have to fall back to another method.
Amazon is another one. If an app like Libby redirects to Amazon, I get a different, passkey-less password prompt, so I need to have a password readily available.
It's great when it works, but honestly 1password with straight up username/passwords is probably just a better UX in the end.