What is the difference between 'Group Members' and 'Members' of a user group

"Group Members" are the people in a group and I believe "Member of" is a group's parent group if there is one (for group hierarchy).

Now can we get a counter? - # of Members - So we know how many Users are actually in a User Group?

https://success.clarizen.com/hc/en-us/community/posts/360006491380-User-Groups-Number-of-Members