If you enter text for an entry page, but neglect to select "yes" in the "Show Entry Page" drop-down, what you've written is no longer there if you go back to the editing page.
I suspect that a very standard error is to want an entry page, enter what you want there, but overlook the selection. It would be better if (a) the 'show entry page' menu automatically flipped to 'yes' when text was added to its accompanying box, or (b) the text remained in the box even if you chose no.