I wholeheartedly disagree. While power-users might "want UIs that are in-tune with their goals and mental models" I have helped my parents navigate computers enough to know that a great number of users have no mental model at all. All they know is that the button that gets to their email is third from the left on the bottom -- heaven forbid you change that.

It absolutely is beneficial to a newbie to say "Oh! This site looks a lot like xyz.com, maybe I can log in with this button."