Count of Roles and Features by Collection will provide you with the names of each role and feature, along with the total number of installs, for a given collection. This information is useful to know in order to help you inventory or secure each role and feature. For example, this report will help you identify all servers with Web Servers (IIS) installed. Once located, these servers can be secured.
This report will drill through to List of Computers by Role or Feature for a Collection, which in turn drills through to Computer Roles and Features.