WayBack doesn't archive videos from youtube, but it could display what the page of a particular video looked like if you had the address and the page was scraped. It can sometimes be used to find out the title and description of a video that youtube completely erased. You might find a link to a video on a website or forum, and the video and channel are completely gone. Take the link to wayback and you may be able to get the title of the video and channel and description, and then be able to find it reuploaded elsewhere. Maybe.