People who do the same kinds of events over and over again (event planners, event venue managers, wedding planners, photographers) find themselves needing to keep track of similar tasks that need to be done a certain amount of time ahead of the event. So, each day, they need to move many different events forward. It can be hard to keep track of this or tedious to set up those recurring tasks in a typical task or project management tool.
Event planning is stressful enough. Your productivity software should help you see just what you need to be concerned about today and keep all the other stuff out of your way.