One could even eliminate those same tasks (not wanting to remember a new password, and not wanting to use a password manager) by setting an unmemorable password

One could even eliminate those same tasks (not wanting to remember a new password, and not wanting to use a password manager) by setting an unmemorable password and doing a password reset using a Gmail address every time they want to log in. "Log in using Google" basically does that same sort of thing but without the tedium of all the clicking/typing. The mechanism is much different but in terms of dependencies it's really the same.