I like it how current game economics builds on precious metals, but as our experience shows - precious metals suffer from constant inflation, which makes it pointless to accumulate coins, and here is the point when economics not working.
From the other side, "platinum coins" can be a good way to bound with ingame economics, and make token trade easier and lot more common. In some way this also helps to spread tokens over players, which prevents excessive accumulation of tokens in hands of top players, and creates a better token sink.
Anyway, i think that devs should think twice before make a decision about this, to ensure this will not make any other valuables useless in game.