If I understand correctly you are asking whether or not QlikSense or QlikView reports and dashboards can update themselves without you physically reloading the data correct? If so, you need the server as well in order to schedule jobs aka updating reports, dashboards and emailing the results of those reports and dashboards.
QlikView has a feature called Dynamic Data Update. It works well in scenarios where you need to provide a real-time update of single rows into the data model. It will not work well for scenarios that try to use the qvw files as the base for a transaction system. Qlik Sense does not have this functionality.
If you don't need to real-time updates to reside in the Qlik data model, there are alternative hybrid solutions to display data real-time within the Qlik Sense app, like extensions.