QV Publisher allows for creating 'tasks' to reload qv documents. Tasks can be triggered by schedules, the success of other tasks, or external events. Without the license for Publisher, you can only schedule reloads based on a date/time. Other types of Tasks can also be created - Distribution, Loop and Reduce, or External Tasks. For example, with Publisher, you can schedule reload of a document, then when it's completed, it can loop thru the values of a field (i.e. 'Region'), and save a reduced QV document for each value of the field Region. Thus creating separate qvw's for each 'Region'. These documents can then be 'Distributed' to a folder, and certain security applied (allow only certain windows groups to read the qvw on the accesspoint).
Publisher is designed for more complex tasks, likely required in a larger organization.