My first day studying architecture at college started with the department head asking me to define the word "architecture." I came up with "architecture is structurally defining environments to accommodate human activities." But when we see "architecture" for the first time, we mostly see walls. Facades define architecture more than roofs, in most cases. There are some buildings, such as churches, where there is "architecture" indoors but when you are trying to locate a building while driving your car, it is the exterior walls that tip you off about which building is which; no one gives you driving directions that say "It's that window building on the corner." Rather they say, "It's that brick or stucco building." The exterior cladding is what defines a building, at least initially and visually. Walls also keep the weather where it belongs-outdoors. This way of looking at architecture-as the wall cladding-has pluses and minuses.
This psychological tendency to label buildings by their cladding puts extra onus on the people involved to make sure that the finished building works well. This includes the designers, as well as the sales people, material producers and contractors. If something goes wrong with a building's "skin," the blame game starts and specialty products are the easiest targets. They are often proprietary systems with specific manufacturers who hopefully (the lawyers pray) have deep pockets.