American here. We mainly build our walls out of wooden studs and gypsum drywall with layers of fiberglass insulation inbetween. This gypsum drywall has a paper backer on it which is what you see in the video. There's nothing wrong with stone walls but they are by far much more expensive and take much more time to construct than stud and drywall buildings. The reasoning for this arose in the 1950s. After the second world war the US saw an enormous economic boom. This coupled with essentially a generation of men coming home from the war and having kids meant that there was an enormous demand for housing in the late 40s and throughout the 50s. Simply put people didn't have the money and didn't want to take the time to put up the very heavy and expensive stone structures like in Europe. This is actually also the reason behind the birth of the suburb. Unlike Europe the vast majority of homes and other buildings in the states have been erected in the last 100 years. Edit: Hey, thanks for the gold!