Locking people into a cell is also obviously criminal if anyone but the government does it.
There are certain powers that are useful for someone to be able to exert at specific, well-defined and controlled times. This is why the government has a monopoly on physical force, and for the same reason it has a monopoly on economic force.
Note also that the government doesn't actually force you to use their currency as a store of wealth. You're really only forced to use it to pay your taxes.
> There are certain powers that are useful for someone to be able to exert at specific, well-defined and controlled times.
I agree with that. But I don't think financially encouraging anyone to use a government-made currency is one of those powers that the government should be entitled to.
> Note also that the government doesn't actually force you to use their currency as a store of wealth. You're really only forced to use it to pay your taxes.
The capital gains tax is an effective way of discouraging anyone from storing their wealth in another asset. Say I had bought gold in 1981 because I (rightly) expected inflation to increase, then in 1986, when the currency had lost half of its purchasing power - and the gold I owned had consequently doubled in dollar-value - I would be legally required to give some of that money back to the government, making the protection of my savings' purchasing power very difficult (if I want to stay on the right side of the law).
So while the government doesn't directly force anyone to use their currency to store wealth, they make it less attractive to not do so. And I suspect these efforts would increase should we experience a flee from the dollar in the future.
Legal tender laws is another type of legislation that gives unfair advantage to the government's own currency. So forcing citizens to pay their taxes in the government's currency isn't all the government does wrt. hindering currency competition.
There are certain powers that are useful for someone to be able to exert at specific, well-defined and controlled times. This is why the government has a monopoly on physical force, and for the same reason it has a monopoly on economic force.
Note also that the government doesn't actually force you to use their currency as a store of wealth. You're really only forced to use it to pay your taxes.