Durability has to do with a currency in use and is not about loss protection. It's more about expiration. Like when the orange you traded for a brick starts to mold or the ink on your $10 bill starts running.
Okay... still sounds like loss to me. Are you generally concerned about others destroying their Bitcoins, and the effect it has on you or "the currency"? If so, why?
Money is information. That's all it is. Who owes what to whom.
So, what does my owning a Bitcoin tell me about who owes what to me? How about a dollar?
I agree that money is information. But it isn't information about
debt. It is information about
supply and demand of scarce resources.
In the economic sense, a "failed" market is a less-than-perfectly-functional market.
No, in an economic sense, a market failure is a situation that leads to less than optimal results due to the shortcomings of the concept of a market itself. Naturally these situations are very rare, but include things like pollution and other externalities. On an economics board, you'd do well to use the jargon properly.
Frankly, given the rather spectacular inconsistencies in the multiple schools of modern economic thought, I think I'd prefer to use words based on their regular, English meanings. And since I'm making more of a philosophical, rather than economic, assertion, perhaps you can just pretend that "market failure" has a more generic meaning than the technical meaning you might usually proscribe to it?
If not, well, then here's my argument. I disagree that "market failure" is a natural consequence of "shortcomings of the concept of a market itself." I think, rather, that it is a natural consequence of something else, force and fraud, intentional harm, ie. crime. In my view, calling this "market failure" is a complete abuse of the language, newspeak even.
Let's say we decide to meet at the coffee shop to exchange Bitcoins for fiat, and you decide to rob me of my fiat instead. Would you call that a failure of the market for Bitcoins? No. That's crime, something "the market" doesn't even pretend to protect against. Since we were in a coffee shop when the crime occurred, is it a failure of the coffee shop to protect against crime? No. The "concept of a coffee shop" doesn't include "protection against crime" any more than the concept of a market does. It's a failure of something else, morality, government, individuals, society perhaps, but not "the market" or "the coffee shop".
So, I'd prefer to use the term "market failure" to mean exactly what it says,
failure of the market, rather than failure of the concept of a market to be so expansive as to include every possible human action. If I'm going to posit a "concept of a market" at all, it would be a complete fool's errand to try to make it dependent upon all the stars in the universe aligning in order for it to function properly and not be deemed a "failure".
That's why I tend to view the concept of a "market" as one of
voluntary exchange in good faith between reasonably self-interested individuals, rather than some mystical all-encompassing pseudo-religion capable of solving all human problems. Externalities can and should be relegated to some other mechanism, the justice system or similar, since I also disagree with your assertion that externalities are "very rare". But that's for another post.