The event management module allows you to configure and manage all events in the database. As a result of using a MS Sql server EPS can handle multiple events in the same database. The maximum size of the database allows for millions of images to be stored and hence it will take many events to fill it up.
The obvious benefit is that you can enable a previous event to allow your customers to browse and purchase from both the current and previous event.
An event that is not active can have all its images removed from the harddrive to make up space, then copied back when returning to an event where you would expect sales of the previous images.