Yeah, I didn't understand the purpose of this device when it came out and still don't. It's an interesting system but seems like worst of both worlds because the coral TPU and M7 aren’t low power enough for battery applications, and it's unclear whether the full 4 TOPS of the Coral is achievable given the MCU’s memory bus bandwidth. So to me it looks like a computationally underpowered system that you have to keep plugged into the wall.

Going with the Cortex A Coral Dev Board or another SBC with the PCIe or USB standalone Coral TPU seems like a better bet. You'd get a better camera (eg via USB), more processing power and memory, and more full featured software (both Linux and TFLite instead of baremetal or embedded OS and TFLite Micro). Price point would be higher for this option, but you'd certainly make that up in saved time very quickly not having to deal with baremetal programming or an embedded OS.