The PI is needed for bridging our PCM3060 based custom sound card(via hardware i2s) with a WebRTC client that connects to the customer. It also handles all the high end internet connectivity and allows us to easily flash the microcontrollers with new software. It could have been done with audiointerfaces instead, but this approach is truly modular and allows us to scale it easily.
Well, it's a well-engineered, -documented, and -supported stable platform to handle computing needs for that giant board. Makes perfect sense, I think.
