One of the interesting points Austrians make about money, is that better moneys drive out worse moneys. I've seen them argue that ultimately there will be one money that is used for all transactions, because that best/true money will be the best medium of exchange and store of value and unit of account.

This thread made me think about that argument and wonder if it overlooked the possibility of different moneys having different comparative advantages. I'd have to give it more thought, but I suspect that either gold or bitcoin would have to evolve or another money will arise that suits both purposes.