Easy.
The USB-C will always work to charge the battery, whatever the module used.
When a compatible module is used, the USB-C will only work in one direction considering how it is connected, hard to tell if it ill be device or master, but considering that there is no way to change the direction (CC1 and CC2 are fixed) this will only work in device mode, so to connect your DevTerm to something, and not the opposite.
Though the DevTerm do also have some host USB-A socket.
Oh and it is a USB-C socket yes, but will only do USB 2. No USB3 speed or whatnot related with USB3.
For the TL:DR about the USB-C socket on the DevTerm:
- It will never work as a host (aka like a USB-A socket) only as a device (like USB-B, microB, miniB, …)
- It will always charge the DevTerm whatever module you use
- It will only provide maximum USB2 speed with compatible modules.