You're able to show images in a very large format, thereby focusing your visitors on the imagery and design itself. Or, if the focus should be on content with the single-column layout, you're able to display the content straight down the middle with no distractions on the right or left (unlike the Content Focused Layout).
On Poco People's website, we are presented with a stunning image that consumes the entire page. There is nothing on either side of the image and the media completely fills the user's attention.
As we can see on Laravel's official blog, a traditional Single Column Layout is used to concentrate on the content. There are no distractions on either side of the content - which runs straight down the middle of the page - thereby focusing the user on it alone.