I find my boots (Surefoot Conformable foamed liners with Surefoot footbed) don't allow such toe movement, and I understand that the images are an exaggeration. I think I do basically the same movements through an effort to raise the arch to engage the little toe side and raise the outside of the foot to engage the big toe side while maintaining some ankle closure. I notice when your big toes go "up and over", your arch rises. What I prefer about my focus (other than that I've been doing it for half a dozen years) is is that I can keep my toes lying on the footbed throughout.
Regarding Big Toe, Little Toe, I think I heard that from Victor Gerdin back before he developed all the wrinkles. I know I was teaching it in 1993 or 1994. At that time, the focus was on the pressing down of the toes into the snow. Since learning about the raising up of the opposite sides of the feet from Sean Warman, I've found that that activity can be more subtle and not cause stiffening of the legs near as much as the pressing down thought seemed to.
I prefer the forward movement of the hips to result from closing the ankle from above rather than from below. Just my taste, I guess. Again, I prefer to have my whole foot contacting the footbed (except the bit I'm raising). I think I'm more in contact with the ski that way.