Our web server has the ability to automatically list all of the files and sub-directories in a given directory to a web browser. Though use of headers, footers, and file descriptions, this is a very powerful feature that can save you a lot of time. You have several directories of documents on your web, which you want to make available to users, but don't want to create an HTML home page for each directory. With ADL, you can provide a list of each directory and bit of additional information about the files. You have a library of documents that is constantly changing.
Colleagues put up new files and take away existing files almost daily.
Keeping a hope page updated takes too much time, but the documents must be available to other users and the public. Thus the directory listing is always current. You have a collection of documents that you want to make available, but a home page would add very little value to the listing. In fact, the home page would simply be a list with links. An ADL saves you the effort of having to create and maintain such a home page.