If debt must be accepted in dollars (legal tender laws) and you have to pay taxes in dollars, then what's the point of bitcons? I don't see how they can catch on when the government basically makes you use dollars. Now If your goal is agorism and countereconomy, then this is as easy to do with dollars as with bitcoins.
The point is that consumers/users of currency prefer bitcoins over dollars in some transactions. They do this for various reasons the first and foremost being that the US Federal Reserve is literally stealing the purchasing power of dollars by creating new dollars electronically and using them to purchase govenrment debts and member bank assets.
I think at the moment the BC is mostly used because of lower transaction costs and anonimity, not as a store of value. However, as it earns good reputation for former, it may get some traction for latter.