When you think about it, the tango scene in Scent of a Woman isn't really essential. You have a blind colonel and a young student having dinner at a posh restaurant. They come across a beautiful young woman who is waiting for her fiancé. And while they wait, the old colonel dances the tango with the young woman. The fiancé arrives, she goes off with him, end of story. She doesn't appear again, nor has her presence advanced the plot or added any unexpected dimensions to either of the major characters. That scene tells you more about the tango than about anyone in the movie.
However, if you ask someone what they remember about Scent of a Woman, their answer will be either this scene or Al Pacino's magnificent rant at the end. Sometimes, that is more than enough accomplishment. That moment has a beauty that transcends its context.