I remember hearing somewhere that the "I'm feeling lucky" button on
Google is only used in a tiny number of searches, and costs Google lots
of advertising money because it bypasses the results page with adwords,
but it's kept there because its presence somehow improves the general
impression of the page.
Maybe screensavers will become the 'appendix' of computer systems in a
few decades. People might ask "Why did my machine come with this
useless thing? It does not seem to have any function, but it must be
here for a reason. What was the original purpose? Was it
evolutionary, and somehow helped when the system was becoming mature
years ago? My system operates flawlessly without it, but nothing is
harmed by keeping it intact. We might as well just leave it and
remove it if it becomes a problem..."
They're sort of like the open/close buttons on modern elevators. The buttons
are silently ignored, but since people *expect* them to be there, they would
react negatively if the buttons were removed.