It will be a lot harder for the government to control E-cash than real cash. Money laundering and tax evasion could proliferate in stateless E-money systems. If the monetary system were anonymous, criminals could use untraceable cyberdollars to hide assets offshore.
That is why the American government is trying to make the public key/private key system that is used by DigiCash and others illegal. The government would prefer for everyone to use their Clipper chip, which is similar to the above method, except that they can also tap in ``if necessary''.
In France cryptography is completely forbidden by the law. Obviously this is currently an area of heated debate.