As a teacher it's "I wasn't able to monitor Tommy's screen while I was helping other students, but Tommy is struggling with the material that he usually gets easily and I'd like to know if he was on task. If not I want to bring back his focus; if so I'd like to understand what he has trouble with so I can help."
If you're thinking "just ask", unfortunately students often don't have that level of introspection.
I have trouble thinking of a use case.