One benefit of Hunt Showdown is honestly letting you find out about new things from different cultures/folklore, with this DLC being a good example.
Perchta is a winter oriented witch from Germany/Austria folklore, who like Krampus would punish the bad and reward the good, albeit maybe more extreme than him. Hunt seems to have taken her depiction of either being beautiful and white as snow or being old and haggard into the two forms this DLC comes with, namely Dawn representing the former and Dusk representing the latter.
As for skins themselves? They are really well done. The Martini Henry skin is a personal favourite of mine, especially with all the little teeth lining the gun. People's biggest issue with this DLC seems to mostly be account of the price, but with how often the game and it's DLC go on sale, I'd say to pick it up around that time, when it's (at the time of this review) 35% off.