If they get damaged shingles are considerably easier to repair than metal.
Shed roof advantages and disadvantages.
Granted they also get damaged more easily.
Since a shed roof generally has a much steeper slope it usually lets the water roll right down it and over the edge.
Pooling water on a roof can cause leaks and other damage.
It does shed rain and snow shed more easily with the greater slope.
A basic roofing design with only one slope is easier and less time consuming to work on for contractors and this translates into lower roofing construction costs.
In the past people used shed roofs exclusively for their garden sheds and garages.
A metal roof is a 100 upgrade easy to repair.
Lots of built up snow adds extra weight to the roof that can also cause damage so shedding water and snow more efficiently is a definite advantage.
Shingles have a lower initial cost.
A simple roof to construct but slightly more expensive than the skillion due to the lower slope needing waterproofing.