HPC is not GPU. It's a whole other area of computing that has little if anything to do with graphics. The Knights landing chips are kinda like a GPU in the sense that there are lots of tiny cores good at one or two operations but it differs significantly from a standard GPU type chip that Nvidia produces in that its x86, and it's cores are a little more general purpose than a standard nvidia CUDA core.
Think of it this way, Knights Landing is marketed as 70 Atom-like cores, rather than 1200 CUDA cores. Because it's x86 you don't need a Xeon in there running command and control for the CUDA cores. The Knights Landing chip can run all on it's own and it has the interconnects and shared memory to run all those atom cores at full pace such that it can do the matrix math just like CUDA but without any of the overhead of a Xeon cpu and PCIE Cuda cores coordinating across the PCIe bus. The advantage is supposed to be that because KL is x86 you don't need to recompile the code to CUDA to get it to run while at the same time getting the same power as an Nvidia build at half the cost.
Clearly KL is making waves or nvidia wouldn't be complaining. The cost of recompiling is massive, being able to run older software on these is a huge advantage, even if you can't get the same speed, especially because it's cheaper than the equivalent nvidia build.