After posting the above, I gave it a bit more thought and decided this deserves a slightly more complete answer.
The blurring technique is one of those wonderful creative acts that forces you as a photographer to confront what is essential and important about the subjects you are photographing. When the colors and shapes, even though blurred, somehow make sense and communicate the essence and beauty of your subject, then you have truly seen something. The process of interacting with the subject and trying to find the lucky combination of camera movement and exposure that will work is part of the joy of the technique. To me, the joy of seeing the subject and interacting with it are reflected in the results, which I find are best with the in camera technique.
For many people, including myself, there is also creative joy in the digital darkroom. One can interact with the images and explore them and try to bring out their nature through processing and printing. If someone finds they can experience and communicate the creative process of exploring the subject through some sort of blurring in Photoshop, I say more power to them. If you are truly working creatively, it ain't faking whether you do it in camera or in Photoshop. But if you are just trying to imitate rather than to see and to create...that is something else. Perhaps that is what Eleanor is getting at when she talks about mimicking.