I dont think his tax evasion concerns are ultimately a very good point. Bitcoin could indeed threaten present income/sales tax systems that rely on perfect knowledge about citizen's transactions if it spreads, but things like land value or property tax would be unaffected by it. If push comes to shove, government will cancel income/sales tax and ramp up those alternative taxes that dont need to take into account your personal transactions or currency you use. Its not true that Bitcoin economy would be inherently untaxable. It just requires different tax approaches than a present fiat economy.
That's true, but it's also irrelevant: Tracking property is infinitely harder than tracking income, any government that tries to finance itself by property taxes alone would have to be massively more intrusive about it than what we are used to. That is not likely to go over well with the populace, I imagine.
I have read Accelerando from Stross, and I am pretty surprised such transhumanist is hostile towards the idea of cryptocurrencies.
You haven't read anything by him since, have you? He has pretty much sworn off the singularitarian mindset in recent years.
Also, as PH said, it's not the concept of Cryptocurrencies that he attacks, it's the specific implementation called Bitcoin that he sees as problematic.
