H-clip usage (20 Gauge Galvanized Steel Clip)

This is an image of galvanized H-clip. As we learned in class, it was used in construction site to hold the sheathing materials and make 1/8" gaps all edges to allow for expansion and contraction. When I researched the price of this material,  mostly it costs        $17.00 / 250pack.
Link : http://www.capitolsupply.com/catalog/pc716-250-pack-7-16-steel-cs718233.html?cid=AFFSAS&SSAID=204502

 

Below picture shows the real example of H-clip's usage. This is a part of exterior wall. As you could see, 

installing H-clips allows OSBs to have approximately 1/8" gaps between two sheathings. 

This is an picture of roof sheathing from inside of the residential house. Along the blue lines, there are clips.