Google's mission is to organize the world's advertising for maximum exposure to Web users. Unfortunately, annoying Web content often overwhelms the page, causing many users to become distracted and overlook the ads.
That's where Google Content Blocker comes in. It effectively blocks all Web site content, leaving only the advertisements.
Good job this idea didn't originate at google. The PHDs there would not have removed all the content - but cleverly introduced a filter to remove only 90% of relevant content and leaving the other 10% of dross in place to "enhance" their ads.