You can get around it, of course, but password managers are aware of the correct domain for a password and will only auto fill it into a form on the right domain. This is phishing-resistant. I'm not saying it's perfect, and I'm a big passkeys advocate. But "randomly generated password auto-filled by 1password" already meets many of the same benefits as passkeys, kinda, so long as auto-fill works on that particular website. Passkeys, in addition to stronger versions of those properties, also provide (1) ergonomics/standardization ("fill" works everywhere) and (2) sites can trust them to be strong.