text: In Harry Potter, though they might not have the technology at the time, it seems that each class they learn a lot, so if a student misses, then they're just super far behind. In this case being able to do the lesson online would allow for the students to never fall behind the rest of their class. Though there are some teachers that prefer getting to teach a student that missed their class, there are many that don't have the time for that, as well as students who can't make it in early or stay late sometimes. Allowing the student to complete the lesson online, saves both the student and teacher some time, though the student may have questions after since they can't ask during the lesson, they could still ask once they go back to school, or email their teacher.