It's the same as with the CPU vs the GPU.
Different task require different hardware.
For everyday device-level AI tasks like running Copilot+, doing local AI inference, or handling multiple AI-powered features at once, the XDNA NPU is the best fit. It's power-efficient and built to handle continuous AI work with low latency.
For graphics-heavy AI tasks like super-resolution in games, media creation, or 3D rendering, the RDNA GPU AI cores deliver much higher raw performance and handle large, parallel AI workloads really well.
Microsoft have been pushing AMD to include an NPU in their chip for Copilot, so it wouldn't surprise me if it's included for the Xbox as well.
Also, the CPU chip is called an SoC, which I believe is CPU+NPU.