Video is the heaviest thing most of us ever attach: screen recordings, camera clips, whole talks. It was born in wherever your camera, screen recorder or download came from, and its real weak spot is nothing inherently; every container brings its own quirks.
GIF is the internet's court jester: 1987 technology that still runs every group chat. An animated image format: every frame is stored with a 256-color palette, there's no audio track and no inter-frame compression. That makes it the right destination when what you need is short, silent, autoplaying loops that work absolutely everywhere.