Obviously, they should exist. Use it when you want to structure your preferences form - like I did in the example. For more details, see the prefernces form section. There is no physical home page anymore. Instead, you maintain a bunch of files that contain a small piece of the home page.
Special snippets are first.snp and last.snp.
They will be served always. First.snp should contain the opening HTML tags, for instance the tags for buttons you want to show etc. If you want to, you can use it for information that will be sent to all users as well. The HTML after the literal statement is sent only when the user already set his preferences. As you can see, a single snippet is not a complete HTML file.