You might be tempted to think an article is the same as a page. Strictly, it isn't. Joomla doesn't think in terms of pages. Joomla figures any web page is constructed of a whole lot of database-driven bits and pieces—and almost any combination of those bits and pieces can turn up on the visitor's browser as a web page.
It's no wonder that K2 powers some the biggest and most popular Joomla! sites ever built worldwide.
These integrated features in K2 not only save site admins precious management time (from managing a dozen extensions which would otherwise be required), but they also allow for better performance.