For Photography you get much more dynamic range to edit the image into different exposures and even tweak some colors. With video, you have only so much dynamic range before the video footage starts to lose important quality. So with video, it's best to get the correct color and exposure right from the start.
Cokin Filters are very flexible for the photographer or videographer on a budget. You get the right filter adapter, and you'll be able to mount the filter holder on all of your lenses. This saves you big bucks from buying a seperate expensive filter for every filter size you might own. Of course these are based on resin (plastic) materials, so they maintaining sharpness won't be like what can be achieved from the $400 dollar glass filters. I'm not a fan of color changing filters, but I do own several Cokin ND Gradual Filters to help balance the bright sun with a darker beach during a sunset. These ND filters are also 'stackable' so that you can multiply how dark you want your exposure.