You do understand this is a false dichotomy? You can have both. Some people would rather watch a video and follow along, whereas others get more out of reading text... and both fit neatly on a page right next to one another.
Documentation is hard. Good documentation is harder. There are many occasions where video and video-like things are good for getting a feel for something and just plain text is good for reference. We shouldn't be saying "just use text because you probably won't bother doing everything you should". We should be saying "Hey, video, still images, and text all combine to make great documentation and help people to understand and use your tool / product." They take time, but we should care about our users, and thus we should take the time to support them.
That's how I did the animations for this Powershell tool.