Animated GIFs are a quick way to reach an audience that favors visual graphics and is inundated with information in other formats.

Also, GIFs are fun!

From Technopedia:

"An animated GIF is an image encoded in graphics interchange format (GIF),which contains a number of images or frames in a single file. The frames are presented in a specific order in order to convey animation. An animated GIF can loop endlessly or stop after a few sequences."  More...