> how do I log in on a device that I don't own? With a password in a password manager I at least have the option of manually typing the password.

I agree with you 100%, although I will say that it seems like newer OSes (perhaps it depends on the desktop + mobile combination, or maybe Chrome + Android is enough, not sure) have a way for you to use a passkey from your phone by scanning a QR code. I still think it's not super user-friendly but it is a clever workaround at least. Most people are accustomed to scanning QR codes, so scanning a QR code from your phone to sign in seems like not too big of a leap. (Although I wonder if it conditions users to scan random QR codes to sign in which could be a bigger phishing problem lol...).