Interestingly, her own character motivations are almost always secondary, and she is acting on behalf of a male character almost consistently. First it is her father, later she is under the influence of a magic potion, that makes her fall in love with Wallace. So even after she cuts ties with Daniel, she is still not acting out of her own will and desires but is controlled by her artificial love towards a man. So her depicted of a witch is reduced to the seductiveness of the archetypal witch, while other elements (like brewing potions, flying on a broomstick and speaking evil curses) shift onto her father. Consequently this depiction is branded by its time and a mirror image of later iterations of feminist portrayals of witches.

Of course there are many elements of supernatural powers and entities of that kind mentioned all throughout Rosemary’s Baby. And yet, even though they are essential for the plot, the use of magic itself is happening out of view - Behind the bedroom wall, off-screen, or in Rosemary’s dream. Even Adrian, the Anti-Christ, can only bei heard crying, he cannot be seen and the only hint at his appearance can be derived from Rosemary’s shocked expression over her son’s eyes. 

This serves a simple cinematic purpose. In movies we are used to see most of what the Characters perceive, perhaps even more. But by obscuring the magical elements, Viewers are incentivised to draw their own conclusions and Imagination to assume what’s happening behind the scenes or out of frame. 

This is even used directly during Rosemary’s Nightmare, where the faces of the present satanists are lighted from behind in such a way, that their faces are cast in shadows. The audience can only roughly estimate their expressions, hence hightening their uncertainty, and – consequentally – their Horror.

During some of the key moments of the movie we can see how Water washes away the terrors that dwell within the dancing school. It is almost exclusively shown in scenes revolving around Suzy Banyon. The first instance being, of course, the heavy rain on her arrival. During her way to the dancing school, there are also fast cuts on flood gates and a storm drain. Generally the instances where water is shown have in common, that the water is always moving, showing a certain pull or current that cannot be halted.

The importance of Water gets reiterated multiple times within her room in the dancing school, either in the bathroom sink or the toilet, always quiet literally flushing away what restrained Suzy (when she flushes away the bland food she got served for example). The symbols on the Windows and Doors of her dorm room also depict a shape that resembles a Water fountain.

The heavy rain, meanwhile, that returns after the climax, while the school is burning down, represents the beginning of the end and the ultimate end of the witches. This way Suzy can also be seen as the initiator of the witches’ demise and the impersonator of the cleansing rainstorm.