It's describing a different type of parallelism - pipeline parallelism. The network is laid out spatially on the wafer in CB's case. So weights are stationary and activations flow. A GPU is going to process the network one layer at a time. GPUs also use other types of parallelism (tensor and expert mainly in inference). Pipeline parallelism doesn't make much sense on a GPU for inference.
I think the point is they need several wafers to fit the model. Data parallelism between requires too much bandwidth (they only have so much edge real estate for io) so you have to do pipeline parallelism with say one layer per wafer. No one does it on gpu unless you can’t fit the model in one fast network domain (which is 72 GPUs nowadays for Nvidia). There is a Dwarkesh episode from like two months ago that explains this reasonably accurately.