Of course, this virtual space is coupled with physical space, by hugely centralized entities called exchanges. To get your money across the border, you need to deal with them. In that case the physical value you can buy with your cryptocurrency comes about from the exchange, not the currency.
Value is a physical thing, not a virtual thing. That’s because we live in the physical, not the virtual world. But we’ll readily delude ourselves into believing that’s not the case.