I disagree with the article on that. Password strength derives from uniqueness and entropy -- nothing else. By this definition, strong passwords are very useful

I disagree with the article on that. Password strength derives from uniqueness and entropy -- nothing else. By this definition, strong passwords are very useful. It's a bad but common security error to equate password strength with matching an arbitrary schema - so yes, by that definition, so-called "strong" passwords are often useless. When a "strong" password is required, most people will unfortunately take a low-entropy word/phrase and perform single additions/substitutions until it clears the bar. Such passwords are indeed nearly worthless.