An older style of décor was to have rich colours and a lot of detail. Chocolate brown walls and multiple framed photos of friends and relatives was the early 20th century aesthetic. Modern styles vary, but most favour an open austere look. People tend to like the feeling of space and neatness.
Window furnishings have also changed as tastes in décor have developed. Older houses had heavy drapes, possible with lighter curtains behind them. Other windows had heavy shutters. While these are fine accessories they often do not have the neat and open that is more favoured today.
Roller blinds take up very little room, both when they are used and when they are rolled away. The blind is a simple shape that often has minimal pattern decoration. This is something that lends itself to open space décor.
Yet blinds serve the same function as curtains or shutters, blocking out bright sunlight in the day and providing indoor privacy when needed. And they do this without being intrusive.