It's easy to ban mining in a country when you control the backbone infrastructure. At which point there is no difference between cryptocurrencies and any other foreign currency.
A brain wallet can be confiscated by rubber-hose cryptanalysis.
It is more resistant, perhaps, to detection than cash on hand in foreign currency (though not necessarily particularly more than a foreign currency account where access information is memorized, depending on the threat profile of concern.)
Torture may be used to find out the user has bitcoin, but you can never be sure you got it all. If they give you access to n wallets, how do you know they don't have n+1?
A foreign currency account is not as easy to setup as a brain wallet.
> It's not hard to see why bitcoin has its appeal, no?
Since I gave the reason (added difficulty in detection, not confiscation) upthread, no, it's not hard to see why it has appeal compared to foreign currency for non-current savings (if you are spending in the domestic economy, which is observable by the authorities, the advantage of Bitcoin is mitigated) under certain threat models.
Actually yes it is. Physical currency inside a country is hardly the same things as Physical or digital currency outside a country. Having bitcoins (etc) inside a country is arguably less secure and far easier to confiscate.
A bank in North Korea is under the complete control of North Korea, a bank in the Cayman Islands is not. Now if you're trying to hide from the United States government then you don't have a huge number of options. But, no government controls all banking.
You still need to move your wealth into bitcoins just as you need to move your wealth into whatever else. So, assuming an oppressive government bitcoins become harder to secure as you still need a foreign bank account but now you need steps after that point.
