Say hypothetically you lived in a place like Cuba where the government had banned things like renting out a room to foreigners or selling them a coffee as was the situation when I was there. Taking payment in the local currency would be kind of useless as you couldn't buy much with it and taking dollars, euros or whatever was illegal and could get you in prison if they caught you. However if your customer transferred some ether to a wallet you controlled with a private key but without your name on it it would be quite hard to catch or prove.

Why would it be quite hard to catch or prove? How many fiber optic lines do you think go to Cuba? They could lock down the internet the same way China does. Maybe they haven't gotten around to it yet, but that's not a long term structural argument for the utility of cryptocoins its a temporary moment-in-time argument. Kind of like how at one point a big advantage of buying things on the web was that you didn't have to pay sales tax -- that's not anything inherent in the web, it was just an artifact of governments' lag.

Say your customers are us tourists and they send from a coinbase account to some ether address. Dunno how they'd track that.

I don't think it's a lag thing - decentralized cryptocurrencies are just hard for governments to stop. Similar how governments would like to stop people paying cash in hand and avoiding tax but have never really been able.

Let’s say you have to leave the country with all your saving. I’d much more comfortable carrying it in btc than cash.

You don't need to hold physical cash to hold USD. You could have a bank account in London, Geneva, Paris, or New York with your pounds, franks, euros, or dollars. If you need to leave the country, your savings are already outside of it. Just like your bitcoins.

The answer seems to be that repressive countries haven't yet put in place effective mechanisms to be repressive with respect to bitcoins. But there's zero reason intrinsic to bitcoin to expect that to continue. On the contrary, since everything is digital the choke points are easier to control, not harder.

How are you opening a bank account in a foreign country as a citizen from Iran?

There are use cases for big money transfer and just "storing" money in BTC, not really for daily transactions.

Good luck opening a bank account in Geneva as a US citizen. Unless you bring really a lot of cash they won't touch you with a 5 ft pole.

If you consider the US an unstable country, I don't know what to tell you.

Not what he’s saying. You can’t open an account even if you are from the us, much less so Iran.

"Much less from Iran" misunderstands the problem with opening an account from the US. Swiss banks don't want to subject themselves to the long reach of the United States government's aggressive criminal justice system. That's the reason they won't open a bank account for a US system anymore. See, e.g. https://www.swissinfo.ch/eng/tax-evasion_us-programme-nets--...

The reason it was impossible, until recently, for an Iranian to open a bank account in Switzerland was not because of the Iranian governments, it was because the Swiss bank was afraid of running afoul of the US sanctions regime. Because those sanction have been lifted (at least for now) an Iranian can open a bank account in Europe, albeit they'll still have to go through a fairly extensive KYC process.

ofc But even opening an account abroad could be tricky.

The thing is that restricting bitcoin is really hard.

Especially if your hoard is ill gotten according to the laws of most countries.