The part about this project that is revolutionary is not obvious. It has nothing to do with the robotic arm. Robotics engineering is a mature field, robots have been used for precision assembly jobs for decades.
And yes, even for drawing. Pen plotters have been around for decades too, and they are basically robots that draw with pens. Nothing new there either.
What is really revolutionary about this is the software used to convert the video image into what an artist draws on paper. Notice that this device isn’t just a plotter, instead it is trying to interpret the image fed through the camera. This is huge, probably bigger than the current technology used to track faces in point-and-shoot digital cameras.