So the monetary value has nothing to do with the use value (and can be much larger - that is even the case for gold whose shear usage value is in fact pretty low). But Austrians started from the idea that in order for an intermediate good to *become* money, it needed to be a highly marketable (and hence valuable) asset.
yes, this is what I understood from Mises.
So did Bitcoin started from nothing ? or can we consider its first purpose when started (buying illegal stuff) could be considered "use value" and not "monetary value" ?
If so, the use value of today is very different from what it was in the beginning. But the "insert into blockchain" I described can't be considered as the first "use value" that made it highly marketable.
Well, my idea is that the kick-off from a highly marketable (useful) asset to a monetary asset is only just one way to get a monetary item. It could just as well start out as something else. If the pure Austrians don't agree with that, then I'm not following them there.
Fiat money started out in another way: it started out as a "proof of holding gold or silver" or was "backed" in some or other way. But now, fiat money stands on itself, as a state-issued token, printed on paper, or even just acknowledged in a computer account.
My point is that a monetary asset is just an asset of which enough people think it is a monetary item. How that collective belief is established, is in fact somewhat irrelevant. It could be by the Austrian way. It could be by the fiat way, initially backed and later uncoupled. Or it could be in the bitcoin way. Maybe there are other ways to establish a collective belief that some asset is going to get accepted by others as money. It is a kind of a bi-stable situation: if most people don't believe something is a monetary item, and hence don't accept it as such, then it is not a monetary item. If most people believe something is a monetary item, and hence accept it as such, then it IS a monetary item.
How an asset transits from the non-monetary state to the monetary state is a kind of mystery, and probably there are many ways. We're maybe seeing, with bitcoin, such a transition with our very eyes.
The opposite transition is also possible: usually this is called hyperinflation, after which the former monetary item is reduced to something like toilet paper (that is, takes on its former simple usage price).