It is easier to watch, guaranteed no sound, and you are expecting getting into short experience (around seconds).
Most don't know it's the whole video before they watch it. When you think gif and click a link are you ever expecting it? But after you start it, you might as well finish it. Just my few cents.
The no sound thing is kinda big for me. I don't like loud noises and hate opening a video, and it's loud as shit. I immediately don't want to watch anything.