The hairstyle is mostly static, but it includes one loose strand which is animated with dynamic motion.
This is a vanilla hair import. It is bundled into the two Snow White costume mods, but please note that those are both Loader mods. You don't need the separate hairstyle SWF if you intend to use one of those MODs -- it's provided for compatbility reasons.
The standalone hairstyle may also be convenient if you intend to play with a nude version of the character and don't want to bother with her costume.