Keeping them is not necessary anymore as it has no use at all.
Bitcoin transcends borders and even if a country has it banned, you as an individual can still use it internationally, if you can properly hide your IP address. You can also still use it as a store f value to hedge against inflation.
I fact, some Chinese people ran away from their homes and live somewhere outside China for this. This is really the best option to do otherwise, you can never spend your Bitcoin or it might be seized by the government and lose control of your crypto.
IIRC, those who moved out of China were mainly miners who could not hide their involvement in cryptocurrencies. However, I do agree with you that leaving the country if you can afford it and it is worth it based on your portfolio, is the best option.