This method is somewhat useful because of the double sided tape use, instead of using pins to baste the zipper. I like to sew the zippers by hand and baste it first with a highly contrasting color thread and a matching thread to sew the final seam.
I find a lot of people do not like to sew and if they can use the sewing machine the better. For me knits do not like to be machine knit or at least if you do machine knit it has to be done extremely carefully. Hand sewing is gentler and easier for me besides I don't have to drag out the sewing machine. But I like the idea of the double sided tape. They are using "Wonder Tape"
but I wonder what will happen when washed? Yes I know they say to only use it on hand washed items not to be thrown in the washer or dryer. But still ...... I wonder?