Imagine a state being able to charge sales tax at the point of each transaction! Or more disturbingly know exactly who buys what for how much and when if tied together with government issued ids and wallets. Or instantly calculate taxes due on income.

Its actually quite scary :(

In fact bitcoin technology or derivative could be used unfortunately to take even more control from people and economies! Its probably a good thing that in most countries politicians would balk at this since they wont be able to get brown envelopes if everyone in the state uses coins