The  benefits of standing seam roofing versus conventional screw down metal roofing.
#1 All fasteners are hidden which give the roof a cleaner look.
#2 No exposed screws to potentially cause a leak.
#3  The fasteners under the ribs allow the roof to expand and contract freely as the clips stay fastened and the panels glide back and forth. Unlike screw down panels, this allows the panels to expand and contract freely.