Here's A Sewing Fact: Closed-End Exposed Zippers Cannot Be Sewn Into A Seam

While most zippers can only be sewn into a seam, a closed-end exposed zipper is cut into the fabric surface and stitched similar to a slash pocket.

Exposed zippers are just as much functional as they are decorative which means they directly contribute to the garment's visual aspect.

Regardless of where it is on the garment, a closed-end exposed zipper has to be stitched into a slot that molds around it's angular lines and houses it in a smooth, flat, tension-free structure. The slot ensures that the zipper teeth/tape remain visible without compromising the zipper's function and design.

If you attempt to stitch a closed-end exposed zipper into a seam, this slot is difficult to recreate due to the bottom stop's square edge around which the fabric should be evenly folded. As opposed to forming two defined right angles, the seam edges can only blend into a "V" as they transition from the zipper to the stitched portion of the seam at the bottom.