Why "Elvira Madigan"?

I listen to classical music while I work. Few classical music announcers are permitted much personality, and they seldom say much about the music they are about to play.  Whenver someone plays Mozart's 21st piano concerto, they do feel obliged to say the music (the 2nd movement Adagio) was used in a movie, "Elvira Madigan", and some people call the concerto after that.

It's a great piece. I have a collection of Alfred Brendel playing those late piano concertos, and it's always tempting to listen to more than one. It's kind of a sin against self to listen to this music while doing something else in the first place, but letting these works blend into each other is even worse.

But why "Elvira Madigan"? Has anyone actually watched or even heard of this Swedish movie from 1967? Why do the announcers feel obliged to say this? What are we supposed to get out of it? It's an odd tic, no doubt originating with some marketing person at a record company. People who feel themselves immune from influence of any kind are often slaves of some defunct marketing person.