Why did you choose 2 cell-phone processors instead of one more powerful processor?

The objective was to maintain a separation of task control. If you lump everything into a single processing unit, you have a single point of failure and a single system by which resources can be utilized. Using multiple processors enhances the system's flexibility. The 410/Windows IoT Core processor doesn't do the real-time system work, that is handled by the RT Controller. The 410 provides system orchestration, cognitive processing, and extensibility. The 820 processor provides heavy stream data processing for cameras and microphones.