Network Wide Text Change does what exactly?

Just as an example, I set it to look for "WordPress", check the box to ignore case-sensitivity and replace it with the name of my network. When I look at the plugins page when signed in, all of the plugins that mention "WordPress" in their descriptions still read "WordPress". If I go to a demo site still running Twenty Eleven, it still reads "Proudly powered by WordPress" at the bottom. So it doesn't change things on the admin side and it doesn't change things on the public what does it do?