Metal roofs are more common in Europe, but have begun to grow in popularity stateside as homeowners search for a roof system that they won't have to worry about replacing again.
No exposed fasteners
There are plenty of metal roofs installed that utilize nylon washered screws to secure the panels to the roof deck. These roof systems typically only last 30 years, the same as high end asphalt shingles. The metal roofs installed by Worker's Contracting utilized hidden fasteners and mechanical sealing of the ribs to provide up to a 60 year lifespan that you won't have to worry about replacing again.
Aluminum mock-up
Metal snips
2-part seamer
Sheet metal pliers