[ARCHIVED] Why would I want to check the box "Launch SpeedGrader Filtered by Student Group"

[glparker]

I've gone through the document here
https://community.canvaslms.com/t5/Instructor-Guide/How-do-I-enable-SpeedGrader-to-launch-filtered-b...

And I can't get it to do anything useful in my course.   I have 21 Sections, and I've created three Groupsets each fully populated with subsets of students.  

No Matter that I set my gradebook filter to, it always seems to pick one specific Student Group as the entry point, and if I try to change, It shows me Sections, regardless of what filters I have active.   

TL;DR, I don't think this feature actually works just yet.   

Is there any better documentation on this feature?  Or can someone point out what I'm doing wrong?