This is covered in the interview with the devs, I especially linked the part where the video segment starts about this.
As for calling it “silver”, gold is the currency of the game covering silver, coppers and nothing changes by calling it whatever you want to name it to trade it. There’s no point trying to circumvent the TOS with that.
This has also been asked earlier on the US forums:
It is best that you leave any feedback on the EU SOD thread, positive or negative:
Or through the ingame suggestion box.