The only problem I see with distributing images as ISOs and rars is that it makes reseeding impossible for anyone who burns the images in DVD-Video format, as the original file is lost (with rared stuff people are also less likely to seed as they have to extract to watch or burn, as most people don't like the idea of having an extra 4 gigabytes taken up for no good reason). Personally, I usually just burn the image files on a data disc, rather then as DVD-Video, as I prefer watching video on my computer monster anyway, so I can reseed most things, but my ratio is already too high as is, so I tend not to reseed things unless no one else can.