Peppering your writing with incomplete sentences will keep readers of your marketing materials more engaged. In other words, they’ll pay more attention to what you have to say. Seriously. (That last statement was an incomplete sentence.)
Good writing needs drama
Too many marketing materials are downright boring, because the writer doesn’t want to embarrass himself by making any grammatical mistakes. If you want people to read what you have to say, you have to challenge the norms and keep your readers on their toes. And that calls for mixing long and short sentences together in the same paragraph. Even incomplete short sentences. (That was another one.)
Yes, your teachers always taught you that was a no-no – and you have the papers with red marks to prove it. But if you’d taken creative writing classes in college, your professor would have most likely encouraged the practice. If you worked in an advertising agency, they would demand it.
It’s like music or painting. First, you’re taught the rules. Then, you’re taught how to take things to the next level by breaking some of those rules.