The Octa RFi is most commonly used for such purposes as fashion, beauty and portrait photography. One of the most important reasons for this is that its unique shape creates a beautiful, natural looking catch light in the subject's eye.
Fashion and portrait photographers requiring a soft, even yet controllable key light favor the smaller versions. The larger version creates a beautiful fill light and has a relatively flat shape, making it surprisingly easy to handle.
Also note that you can transform the Octa RFi into a parabolic reflector by simply removing both diffusers!