There are quite a few advantages to using roofing shingles over other types of roofing design. While roofing needs vary depending on weather conditions in the part of the world you're in, shingled roofs are the most common type to be found in most of the United States and Canada.
Shingles are basically small roofing tiles which are used to cover a roof. They are stacked in an overlapping fashion across the length of the roof, allowing rain to slide off easily. One of the biggest advantages to using shingles over, say, a single metal sheet (a common roofing technique in some Asian countries) is that it provides the house with better ventilation and heat management.
In the summer, hot gases, with their tendency to rise, will see out of a house through the gaps in the shingles, leaving the interior of the house cooler. In the winter time, however, the shinglees become packed with snow, allowing the roof and the snow itself to become a heat-retaining layer of insulation which helps keep the interior of the house warm.
Shingled roofs are also generally sturdier than single-sheet or standard concrete roofs. The tiles are tough yet, because the roof itself is not made of a single piece of material, the overall effect is one of flexibility under pressure. Where a solid piece roof would crack under sufficient weight, shingled roofs provide a certain amount of "yield" under pressure that keeps the roof intact.
Lastly, one of the nicest advantages of roofing shingles comes during repair-time. Whereas one-piece roofs need to be overhauled almost entirely for repairs and can get expensive, shingles are small, easy to install, and cheap to replace if they get broken.
There are, however, two major drawbacks to using shingled roofs that make them inapplicable to some climates. The first drawback to shingleed roofs is that their tiles are more vulnerable to thermal stress. Thermal stress does not mean mercly extremes of heat and cold, but rather returns to sudden and drastic changes in temperature.
Being composed of small tiles, sudden changes in temperature from high heat to cold or vice versa leave the shingles more brittle and prone to damage, sometimes even actually causing them to suddenly crack under the rapid temperature change. This makes shingles inapplicable in certain tropical climes where a blazingly hot tropic day can suddenly be punctuated by an ice-cold rainstorm.