The scary cousin of this antipattern: the login form that browsers' built-in password managers can't see. Building the DOM using pathologically dynamic methods, using nonstandard input fields, giving the username/password fields ridiculous names, etc.
This tells me that the developers don't use password managers themselves, which means they probably use hunter2 for all their passwords, which means they don't know or care about conscientious security practices... not the folks I want to have built the site I'm about to use.
Agreed, I always double check that the browser password manager works, but it's tricky because there is no standard around what the fields should be called to make it always work. The best way to make sure it works is to put the username directly above the password in the same form, that will result in most password managers working, and this is especially important on registration forms.
This tells me that the developers don't use password managers themselves, which means they probably use hunter2 for all their passwords, which means they don't know or care about conscientious security practices... not the folks I want to have built the site I'm about to use.