Since DSLR video camera are incredibly light and not very ergonomically friendly for handheld work, using them without some type of stabilization system can render many of your shots unusable do to unpleasant camera shake. This camera shake draws audiences’ attention to the camera, which breaks the 4th wall and 
the illusion of reality, which as a director, you’re trying so hard to create.
At this moment, a shoulder mount is a necessary accessory. A shoulder mount is a dynamic piece of equipment that moves with the DSLR camera operator. It is not static like a tripod and it allows you, the filmmaker, the flexibility of movement, the shoulder mount can really help increase efficiency during production.
Essentially, a shoulder mount camera helps filmmakers create a sort of visual metaphor for something happening in the narrative of the film.