But here's some more specific reasons. It can be a virtual yearbook on-line.
Kids love it, so do parents on school-visiting days.
If you belong to an organization, a sample web page is something to show your bosses and your board, to explain how your organization can benefit, and share info with as many of 33,000,000 people who might access your pages. If you belong to a business, same thing. Make up powwow announcements. Put a sample Tribal newsletter on. Add links to other native web pages that show off something similar to what you hope to do.