The advantages of pre-recorded video in the classroom
Findings showed that using video instead of other teaching methods resulted in small improvements in student learning, whereas using video in addition to other teaching methods resulted in larger improvements.
The article discusses the various advantages to using pre-recorded videos as supplemental materials for lessons. Students can start, stop, and rewind as much as possible, whereas the teacher can edit the video or re-record parts of the video to help get the information across to students.
Although the study looked at the university level, I didn’t see anything that would preclude some of these advantages working at the K-12 level.