I’ve never seen someone who looks good in photos but not videos, but I suppose it could happen if they only have one or two really good angles. Most people look different through a camera lens or in real life, though, some better in one or the other, some good in both, but still different.

Photos are generally composed, so someone can easily be photogenic from conventional photography angles and always look good.

Video is often never composed frame-by-frame to the level of a photo, so it's a lot more likely to get less than flattering angles, which would lead to this.

I think someone being video-genic would probably be less common than photogenic because it implies you effortlessly look great from any angle