Possibly tagging certain campuses if you are a multisite campus, or tagging specific service times. These tags could be custom and help you develop more custom dashboards and reports.
We use tiers to describe campuses based on their financial viability and contribution toward central expenses as well as campus expansion efforts. So in this context tagging a campus tier 1, 2, or 3 could pull some interesting data. Or for churches running multiple styles of worship or languages you could tag a service according to those as well.