When a course concludes, your learning mastery data (performance on outcomes) is no longer easy to find. An administrator has to manually add all concluded students back into the course to view this data. Canvas needs a simple way to observe how your students performed based on course outcomes after the semester ends. The new gradebook allows a teacher to view grades of concluded students, but this feature does not carry over to learning mastery. Including the same filter options in learning mastery from the new gradebook would be a quick fix that could save headaches for instructors later.
This doc demonstrates what I'm talking about on the grades side: