The single main reason why you would choose a standing seam roof system is because it is a better system, and the main reason for this is because when properly installed,
no fasteners are visible, nothing pierces through the panels to attach it to the roof deck. This is all done under the panel, which minimizes the chances for leaks.
Corrugated roof systems are installed by fastening through the panel into the roof deck, meaning the panel is now pierced.