The original Office 365 Groups expiration policy was pretty good. It helps tenants keep control of potential group sprawl by removing old groups based on age. Now the policy takes user activity into account. While still not perfect, the new implementation makes the group expiration policy even easier to use because owners don't have to do anything to renew their groups if the groups remain in active use. You might debate the set of activities chosen by Microsoft to represent a good signal of group activity, but not the way the policy now works.