For buffering, since there might be a network hiccup sometime in the future. But generally also a better user experience if the user wants to skip a few seconds

For buffering, since there might be a network hiccup sometime in the future. But generally also a better user experience if the user wants to skip a few seconds/minutes forward. And I guess the bandwidth required also depends on the video bit rate/format/compression ratio, so you need to implement a lot of smarts to make sure you don't serve something too slow or too fast, and still people would be able to download the video, albeit at a slower speed. So, basically, it's not worth it.