Not true. Using your example, you'd first need to convert your Francs into x-coin. If convertibility is illegal, then congratulations you just entered a black market.

Which is fine if that's what you want to do, but now your risk just increased dramatically. Is that kind of risk taking scalable for a mass market? I doubt it.

As to it being an asset and not a currency, there are many things that do that, but x-coin isn't that because it has the functions of a currency: Store of value, medium of exchange and unit of accounting. In your example, you're using the coin as currency to intermediate an exchange of [mansion].