I believe photography is about capturing moments that should be remembered forever. Just having a photo that accurately portrays how someone looks on a particular day or in a particular place can be good. But capturing the person in a way that tells a story is much better.
This particularly applies to any performing art. Dancing is a performing art that is telling a story. Listen to the instructors and pay attention to how many times they talk about expression, not just with your face, but with your whole body. Each choreography is telling a story. It has ‘accent’ points where the facial expression combines with a particular movement to stress an important element of the story. These are the precious moments I believe should be captured to save forever.