Bitcoins are in a novelty stage now. Once the big central banks feel the threat the government will shut the whole bitcoin operation down. Anonymous email websites were shut down for much less. It will take a simple declaration that terrorists use bitcoin and good bye all your bitcoins.
You do realize *coins are in multiple countries? They are not restricted to the U.S. only There are multiple markets and the distributed nature of *coin architecture is far more complex an issue than shutting down e-mail servers.
The novelty phase has Chase gearing up their own crypto currency, only theirs is more centralized unlike the current architecture that is de-centralized. In early 2014, bitcoin (and litecoin, a few others) are going to explode with the advent of ASIC designed mining rigs. The “next” blocks of the ledgers are going to be mined very aggressively.