Why? It was made in 1948, when it was still acceptable in America to have open/honest religious feeling in public, so the film's tone is not apologetic, as later versions are. Bergman is utterly immersed in her role and radiates "purity" above "sexiness", which modern film makers tend to emphasize to please the marketing people (among others). In 1948, "production" aspects of film (plot, characters, "significance" of story) were paramount; and marketing was secondary. The order is reversed today, sadly, so films sacrifice "significance" for "popularity" ...which dates the film quickly.
Review of Joan of Arc
