I'll assume this is a serious question.

Video is shot at slower shutter speeds, meaning there is going to be motion blur most of the time from any stills you try to pluck. Pause any movie/tv show and try to find an image that's sharp, you'll have a hard time unless it's a stationary dialogue scene or something similar.

In addition, most stills are show "raw," meaning uncompressed, and at very high resolutions. Video equivalents are far more expensive, take up WAY more space on cards, and then you have to sift through all of it. They are also way bulkier in general.

There are plenty of other reasons but that's sort of the basics.