If one disagrees it is not all that persuasive. Had it been in the body of a longer letter it probably would have been a helpful piece of substantiation. The letter is too brief - which it had to be because it has been placed inside the front cover. In short this letter lacks meat and persuasion. The quote I referred to originally probably does more for the company than the letter, particularly because the brochure is peppered with such quotes.
Advertising is the greatest art form of the twentieth century.