TLDR: The final step in the ID check is submitting a video for a liveness check to verify the person matches the ID photo and prevent fraud.
Recording a Video
When completing your ID check task the last stage is to submit a video. This video is a liveness check to ensure that it's a real person submitting the video.
This prevents anyone from using technology to pretend to be you and submit this fraudulently. We also use the selfie and video to check that the ID belongs to the person submitting it by matching your face to the photo on your ID.