I like rain skirts, or sometimes a poncho which is sort of like a short-sleeved rain jacket plus pack cover plus rain skirt all rolled into one unit (that can also serve as a somewhat minimal shelter ...).
I've layered a very light wind skirt with rain chaps a time or two, because a wind skirt can be frustrating to use when there's significant wind. The wind sort of blows the skirt open and up; you can try to connect the bottom of the skirt wrap (depending on which skirt you have) but this can be a PITA and/or make it harder to walk if you snug it up enough against the wind.
So if it's cold and windy, my preference is rain chaps or no lower body rain cover. Still, on long trips when I've had the wind skirt, I still put it on when it's cold + wet + windy. So long as you accept that it's going to flap open some, it does help.
In less windy conditions it's great --- the concept is excellent IMO. Keep the upper parts of the legs warm and you've got most of the value IMO of rain pants, while allowing for ventilation with a piece of gear that's much easier & faster to put on and take off.
I've used the Packa, which hangs pretty long and so has some rain skirt effect (rain mini-skirt built in? :-)). Overall now I prefer the flexibility of a very light rain jacket plus one or all of Zpacks cuben pack cover and rain skirt if I want that level of coverage.