Do you not believe a bitcoin black market could be formed? Especially when the state becomes more pervasive perhaps imposing price controls when inflation gets out of control, people may turn to bitcoin because at the moment it's far better than any other cryptocurrency out there at the moment and when the economic situation gets worse dollars or SDRs or whatever we're using in the future just will be hated by the people because inequality will be so great and the poor will be really poor.
Black market won't function so well because anonymity is broken for all due to footnote [2] in the OP. Due to the coin tainting by authorities explained in [2], then it will be very difficult to find someone to transact with you. Most will refuse. If you want the coin to function well, you have to prevent coin taint from fracturing the money system.
Coin taint is perhaps the most serious problem in Bitcoin. A core Bitcoin developer is trying to fix it with CoinJoin, but I explain in [2] why that won't work.
Also we are headed in massive deflation, not inflation. Please see the long list of armstrongeconomics.com links I provided which explain this upthread.
The way socialism collapses over and over again throughout human history is the people support the government to go tax+confiscate the rich. Eventually the rich becomes the middle class, e.g. look at what Obama is doing and IMF is proposing a 10% confiscation of all bank accounts. By the time the system is eating itself, the people don't have any money. Thus they demand the government to do more to tax+confiscate. This is a downward spiral into the Mad Max abyss. It has happened many times in human history, e.g. the Wiemar Germany then Hitler. But that is not the only example, there are 100s.
So yes we need that anonymous cryptocurrency and thus black market. My hope is it becomes as mainstream as possible. Else everyone sinks with the Titantic.
When the IMF confiscation comes, there will be a mad rush into Bitcoin and also (by the more astute) into a more strongly anonymous coin that doesn't have coin taint. When the authorities start tracking down Bitcoins and pushing the coin taint to reality, then a mad rush (of the less astute) out of Bitcoin into the more strongly anonymous coin.
Do you really believe the US government will choose deflation over inflation? Most academic economists want inflation at the moment and are not even worried about hyperinflation due to the low velocity of money, that's what the QE has been about hasn't it? They're trying to reach an escape velocity and increase consumer confidence before dialling back the QE and raising rates. Armstrong says it's impossible to maintain our reserve status and inflate our way out of this problem which is true but why then have they not started the deflationary measures already?