Normally you can use all basic function of Revolution Slider plugin you saw on demo site.
However you have to purchase separated license for Revolution Slider if you want to use additional features ex. auto update feature of the plugin. When you purchased theme, plugin is included but it’s purchased code for theme so you can’t use it for Revolution Slider.
This limitation is added by Revolution Slider plugin author so we can’t change it but from our experience almost 99% of its features are available only some features which is optional like auto update, sample slider template.