This report is useful to show adoption of features specific to Office 365 Groups. Note that use of Groups does appear as a service in the Active users report, so you'll need to review both reports to get a complete picture of end user adoption in your organization.
There are several aspects to the Groups report, and the charts don't make these perfectly clear. So, let us take a moment to review each one.
The Groups panel shows you how many groups have been created and how many were active. Because Office 365 Groups can be used for security and synced with a local Active Directory, it is not unusual to have many more groups in existence than are actively in use.
Office 365 Groups Activity by Amount and Date Chart ...
