For an A-list game, I can see a video being a benefit.... if it's well done. Let sellers that are so-inclined do that on their own initiative, it lets them set themselves apart. A good video can help a reputable seller with a good machine acquire top-dollar.
But for guys like me that deal in lower end machines I just don't see the effort being worth it. I often buy games with minimal photos under the expectations there are issues. Getting all working displays and a manual is considered a happy surprise. Half the time they aren't even set up, or aren't working, so a video wouldn't be of any benefit.
That and being able to post a video is very different from being able to actually make a usable video.