Private banks can create obligations called loans because they are licensed to operate in a state and have a deposit at the central bank. The state is the one with Power (capitalized as in- a thing), the Power that protects property rights or even to define property rights, the power to levy taxes, the power to issue licences, the power to control land and resources and say what can and cannot be bought to market.
The first and second sentences form a non-sequitur. Yes, banks are licensed to operate in a state. But no, beyond this there is no inherent requirement that the bank have a deposit in order to make the system work. Our central bank makes that requirement, because it sees this as good governance. You could have a system with no deposit, though.
In particular, it is worth noting that in the absence of a state, there would be nothing preventing private banks operating exactly as they currently do, only with knobs on. A totally deregulated banking sector (deregulated because there is no regulator) would make those loans in exactly the same way as they currently do. It's not the state that controls the money supply, it's the banking system. An awful lot of people on the libertarian side in particular don't seem to understand this.
If anything, the state acts as a
brake on this ability of banks to create money. No state, the whole thing accelerates. Look at what was happening with payday loans, for example, before it got heavily regulated.
And this is basically what is happening with bitcoin. A deregulated bank has started printing money in the absence of state activity.
But what happens next? That is addressed by considering your next argument...
states didn't bother themselves asking what gave gold value back when they used gold as money, and they didn't need to ask what gave gold value when they chose to stop using it as the base layer (plus Ceasars profil) as currency. States created currency in the first place, super-novas created gold, if people like and value the shiny yellow metal then ok that's something the state may or may not choose to involve itself in on the level of policy and using gold (depending on what other states think I guess- maybe after a big war they'll get together and have some big conference where they all decide that from now on they'll all recognize the use of one particular states currency to trade in commodities with).
You're too hung up on the valuation of gold. The value of money has nothing to do with the appeal of shiny metal, which is why states could abandon gold and see the wealth of nations increase rather than decrease. Again, this is a common libertarian mistake (not that I am making an accusation, just stating a fact).
The value of money is that it stands in for the collective power of and trust in the state. It has that because the state collects taxes, which it uses to pay its citizens for the activities they do in the name of the state. It also has that because private enterprise that operates within and using the infrastructure of the state operate by using the local money as its unit of account. Anything could be used as that unit of account -- gold, conch shells or just numbers on a computer -- and the value would be the same because it derives from the activities of the society run by the state.
Bitcoin's out there being valued by people, whether other people like it or not and whether they see the point or are in any way interested or not. For now... that really is all there is to bitcoin re value.
And that's why (a) it's not money; and (b) it's a pyramid scheme that will eventually burst. It's not pegged to anything and it doesn't derive its value from tangible economic activity. Nothing is holding it up other than sentiment.