The use of a steadicam allows to create astonishing visual and emotional moving shots and offers freedom to the director and the DP to place and move the camera where and when they want in order to tell their story.
Shots like the 3 min. Copacabana shot from Goodfellas (1990, Dir. Martin Scorsese) or the 5 min. Beach at Dunkirk shot from Atonement (2007, Dir. Joe Wright), the shots in The Shining (1980, Dir. Stanley Kubrick) are some examples for great storytelling shots and their influence on the perception of the film.
This is the trailer of a short movie called Orientierungslos by Lara Mack I worked on last summer. Part of the three minute longtake made it into the trailer.