Although it makes installation more difficult (tight fasteners will spread the metal), I have done 4 roofs with driving the exposed metal screws through the rib of the roofing metal. Metal needs to be predrilled or punched to start the screws on the ribs but keeping the screws out of the water channels greatly reduces the risk of leaks if you don't want to spend big bucks on standing seam/hidden fasteners.
Most of the traditional Alpine Chalet style roofs are low slope designed to keep snow in place...
I don't have a picture with the roof loaded... but, it does happen.
We have a hidden fastener,raised seam roof and love it. Ice stops are not only for safety,but also to save your gutters,almost lost our the first year before I got ice stops installed,and they clamp to the raised seams,no screws. Only penetration is the plumbing vent and plumber hooked all together so only one.