It would be helpful to have the seating chart functionality in activities as well as in classes. One example would be a chess club, where the students are matched and moved. Having a seating chart helps the teacher learn the student names, keep track for attendance when not officially required, but is still "nice to have" information.
As of the 1/18/22 release, seating charts are now also available for advisories and activities.
Forget about chess club and "nice to have".. Most schools take attendance in homeroom, which is an activity group because it is not graded. This is essential basic functionality! It was built so nicely, but unfortunately without this, it's useless to many schools.
It would also be helpful in Advisory because at our school Advisory meets as a class and attendance is counted for it.