Until you cross the borders and move all your wealth with you by memorizing 12 words.
Sadly there exists no sure way to secure you belongings if the other party is sufficiently motivated to strip you of them (or your life)..
You can also be killed/robbed outside of your country by intelligence officers of your country...
There are always edge cases, where nothing helps. Fortunately, most countries are not like North Korea and you have some freedom, often enough to use crypto.
It is much easier for the government to confiscate your money from your bank account than to go after your Bitcoin. And it is impossible for the government to stop you from accepting payments in Bitcoin and to cut you off from financial system.
I live in an old and free democracy in Scandinavia (in the EU) and actually believe in my government's mostly pure motives. Our laws are solid and confiscation is unheard of outside of criminal activity.
If that changes drastically, I am screwed either way...
And it might be impossible for my government to stop me taking bitcoin but they could surely hinder me in converting them back to regular currency. And in my country nothing can be bought by any cryptocurrency.
But would said unfortunate person have access to a passport and are they allowed to leave their authoritarian country?
Do they have anywhere to legally go, where they have the right to residence and can get into the new countries banking system? In the EU at least that is NOT easy unless you already have citizenship in another EU country....
I.e. say you are that person in that country, could you just decide to leave with your twelve word password, your passport and a backpack. And could you setup life in another country?
I do also see the value of storing your money in bitcoin due to inflation, if you believe bitcoin is here to stay (I don't believe that), and you can manage to buy it without too much suspicion from your state and convert it back at a later day if you decide to stay in your own country.