Would you call the first box special or high-end? Is the second one plain? Forgettable?
A fellow career advisor was fond of using both props in presentations. As you’d expect, it's a great way for people to visualize the importance of personal branding in documents like cover letters. Moral of the story: Even if a cover letter isn't requested and/or you think it won't be read, include one anyway. Expensive jewelry may not be your vice du jour, but the underlying message is clear: you want to be the memorable box.
(And by the way, memorable means a tailored document meant for that particular position, not a generic form letter.) A well-written letter gives you a way to differentiate yourself from the competition; don't waste the opportunity!