The Rollups tab is a simplified view of the Reporting tab.
From Rollups, you can simply see a list of organizations that you are connected to, the total lifetime raised, and number of campaigns.
If you click on the three dots to the far right of the affiliates or organizations, you can quickly see a list of all campaigns or payments that have been made for that organization.
This is the same information that is present on the reporting tab, but in a condensed view.
For admins who are part of many dashboards, the Rollups tab may be the easiest way to find what you're looking for!