Consuming the ODB port for autolaunching an app seems like a really pointless addition. It weirds me out that I'm installing an always-on (when driving) computer in my car when it provides no major benefit other than knowing when my car is in reverse -- and since I've got to set up my phone anyways, opening an app is not much more work to save from having an entire separate dongle needed.
The OBD adapter does serve a very important role in the system in that it has a power source and can wake the camera frame when necessary (before you ever launch the app!). All of our vision algorithms also run on the OBD adapter, which is a key aspect of the power model.
I think the remote wake is based on when the car is put into reverse, which would be challenging to tell from the phone. I imagine that only running the camera when the car is in reverse is a key part of keeping power consumption down in the frame.
I assume it runs in low power mode most of the time, and is woken up by an RF signal from the dongle. It's _possible_ you could accomplish that via BLE from the phone, but maybe not.
Obviously the camera can't be on all the time, as I'm sure they're cutting the power budget pretty close as it is, given the size of the solar panel.