I have a skirt with that style zipper at the waist. It is similar to the mexican circle skirts and in fact has a Mexican novelty print with pottery, sombreros, etc... but it is American made.
I have always thought it was the neatest zipper. It allows for a bit of adjustment as you can "lock" it down at any point once the slide part is in place. Probably allows for an inch or more play at the waist.