Gold is susceptible to global adversary (government) attacks. You can't have instant payments over internet with physical gold -- you need some kind of virtual banknotes to change hands instead, and to be redeemable in physical gold sometime later. That would be perfectly fine in a world with small, reasonable governments, but in the real world we live in, it's not. Two problems arise:
1. Sending physical gold for payment clearance, especially though state borders, is problematic (just plain illegal in some countries, may be taxable, etc). Doing it often and in small portions is also economically unfeasible [you need economy of scale to lower security costs, logistics, etc]. The usual market solution for that is creating big clearinghouses, with branches everywhere, etc. But:
2. Running a big clearinghouse for gold makes you effectively a bank. Running an unregistered unregulated bank is a crime in most countries. So you have to register, get all the licenses, keep all government requirements fulfilled, you can be subjected to all kinds of inspections, etc. On top of that, in some countries gold payments violate legal tender laws or something else, and since you are already on gov radar, it's a non-starter. After E-gold crackdown, we know these are not purely theoretical concerns.
Bitcoin is free from these limitations. Instantly redeemable, no vulnerable physical storage, distributed, no need for high profile points of failure, etc. Bitcoin still lacks one of the standard requirements for commodity money, though ("must have some non-monetary use/value"). How critical is it? We'll see :)
OK, I take it that from government attacks you are referring to gold seizure in E-Gold and during the Roosevelt era.
I don't know if this can be avoided. Governments could coerce the release of private keys so that the BitCoins could be reassigned to another party. (by the way, what happens if the private key is lost?)
During the Roosevelt era, it is simply outlawed, and gold has to be exchanged for fiat currency. I'm not sure if BitCoin can circumvent that.
To seize noticeable amount of bitcoins, you have to work through individual bitcoins holders. Bear in mind that bitcoin transactions are not channeled through any central points under gov control, nor are they automatically personalized -- so the gov must first somehow find out where to look. The whole process will take months, and the borders are effectively transparent for coins all the time. If you know the seizures are underway, you may as well arrange for your coins to stay out of your access and U.S. jurisdiction for a while.
To seize noticeable amount of gold in gold-backed paper money system, you have to issue one order to all registered banks. It takes a day or two.
But that's besides the point. Nothing will circumvent the confiscation scheme in which the attacker has power to do anything they want to you, and you can't do anything to protect yourself. It's simply not the problem to be solved by monetary system.
1. Sending physical gold for payment clearance, especially though state borders, is problematic (just plain illegal in some countries, may be taxable, etc). Doing it often and in small portions is also economically unfeasible [you need economy of scale to lower security costs, logistics, etc]. The usual market solution for that is creating big clearinghouses, with branches everywhere, etc. But:
2. Running a big clearinghouse for gold makes you effectively a bank. Running an unregistered unregulated bank is a crime in most countries. So you have to register, get all the licenses, keep all government requirements fulfilled, you can be subjected to all kinds of inspections, etc. On top of that, in some countries gold payments violate legal tender laws or something else, and since you are already on gov radar, it's a non-starter. After E-gold crackdown, we know these are not purely theoretical concerns.
Bitcoin is free from these limitations. Instantly redeemable, no vulnerable physical storage, distributed, no need for high profile points of failure, etc. Bitcoin still lacks one of the standard requirements for commodity money, though ("must have some non-monetary use/value"). How critical is it? We'll see :)