i think major benefit of btc that no third-party seizure since there are multiple redundant copies of the transactions database, no one can seize bitcoins.
did you mean that there is no way for a third party to intercept transactions of bitcoins, and therefore there is no viable way to implement a bitcoin taxation system.
it is important in terms of tax but i think than other important thing bitcoin is completely global and subject to few laws and restrictions from central or other banking institutions.