For example, some recipes include the accompanying photos inline, while others collect the photos at the end. If instead, the submitter merely tagged the photos according to what step they accompanied, then the website code can lay them out beatifully in a number of different ways to suit different viewers.
I think I'm thinking something along the lines of LaTeX philosophy: You provide the content and leave the layout to the experts/computer. So you don't write that "Zest of 2 lemons" should be part of a bulleted list, you write that it is an ingredient and leave it to the layout to put it in a suitably formatted ingredient list.
Another advantage is you reduce the ability of less savvy users to make parts of your site look ugly.