At work, I make sure anyone around me isn't watching my hands, much less my screen. I get what the guy is saying in the article, but I don't agree, either.
I suppose I type fast enough (and use a password manager widely enough) that I haven't ever worried about keyboard passwords, but I do worry about bank card PINs... I've gotten a habit of obscuring my pin by pressing with several fingers on the keypad for each keypress -- so to someone looking, I'm basically mashing several keys, but at each mash a different finger is actually pushing a bit harder than the others.