Probably not waterproof, but the part is very solid and robustly built and the USB-C socket is provided with a plastic protection, i.e. it will definitely withstand splashes or light rain...
Hello Sherlok
Yes, it costs that much. Unfortunately I can't give you any more information yet. This is because mine is in repair and does not work together with my camera.
GoPro has confirmed that the feature cannot be turned off. However, we have passed on your input to them. However, it is not certain whether this feature could be added with an update to the firmware.