I think video will help most photographers become better photographers. With video there is no cropping (OK I know you can some but lets not) so you are constantly trying to maintain a good composition while shooting. The better you get at doing this the better your still photography will become. Still photography is much harder than video since you have only one frame to communicate the story. So any tool you have to help improve your skills should be used. In video you can sometimes see how the frame changes and say 'that is the shot', you are training your eye to see and your brain for when to push the shutter button.

I'm not saying you will ever want to become a videographer I am just offering up a new tool to use to improve your work.