The Drop Down View component provides a listbox for display elsewhere on the site, based on data from a Query.
The usual reason to provide a standalone dropdown listbox as provided by the Drop Down View is to provide easy access to one of a set of pages, all based on the same Form.
For example, if the Form contains product data, then the Drop Down View could be embedded on an introductory page. The Drop Down listbox rendered by the Drop Down View would then show a list of all the prduct names, and selecting one of the names would take the visitor to a page containing product details. To enable this to happen, the field in the Query that the Drop Down View is based on has to have its link settings set to open the page with the product details.
Note that the Drop Down View displays only a drop down listbox - there is no 'submit' button to cause the new page to appear - simply selecting an entry from the listbox is sufficient.