Have you heard copy is king? It is a longstanding concept taught for generations. I heard it at college and my first ad agency job. I have seen many ad agencies perpetuate the concept when the management team comes from sales and copy departments.
A headline is a powerful element. It draws reader in, but not if it is only 12 pt and a light font. Design is the first influencer that determines whether the audience gets captured and drawn into the sales process of the package.