As I understand it the problem here is that the connection between the camera and the sync module is for very low bandwidth data, using low frequency radio, which is very power efficient. They call it LFR in their notes or when referred by support, etc. The purpose of this connection is to periodically send a few bytes of data only, to make settings changes, and get status updates from the camera, and no doubt a few other control signals, etc, and I suspect this connection is not suitable for for streaming high bandwidth video.
We can sort of confirm this is the case, because we can’t use the sync module as a way to hop a little further, between the router and the camera. The camera has to be able to see the Wi-Fi of your router directly, and this limits the range. If the video went through the sync module, then everything would be going through the sync module, and we could get 200 feet, with the right arrangement, and there would be no need for a Wi-Fi to camera signal strength indicator, because it wouldn’t be connecting to your router, at least not directly.
I think as Joel_Ek suggested, if you want local storage, due to volume, or flaky internet, you might need to look at another system. Also, as Mark said, even if they were to implement it, if it were possible, then you’re not going to hear about it in advance, to help you make your decision, because they never reveal anything in advance, or at least not recently, since Amazon.
As for what the USB port was intended for, who knows, but they have said it’s inactive, and unsupported.