Why do so many dealers put a video on their car listing that is nothing but a slideshow of the pictures they already added?

Actually I don't think I have ever seen a dealer video that genuinely walks around the car, starting it up and showing its features, but I suppose that's understandable considering the effort they would have to put into each listing.But even then, compiling all the pictures into a slideshow with music and a cookie-cutter commentary for each car also takes quite a bit of effort. Why even bother?Example via /r/cars http://ift.tt/2uQDL3g