Buttons, headers, icons - they all have their place in making a full interactive experience. "The whole is greater than the sum of its parts" is a cliche that rings loudest here, since even a single page with just one giant clickable button smack in the middle of it hits home in a way that outpaces the giant button alone. This is not to downplay the importance of details. Conversely, any well designed site will naturally draw attention to its details the more the user navigates it, so long as its elements are consistent and weighed by importance. Therein lies the artistry.