Bitcoin and other crypto require a well functioning internet infrastructure, otherwise it's just data on a hard-drive. Disconnect a country from the Internet (or filter the traffic) and you're forking the chain. Spend on both networks by buying other (unfiltered) crypto. There are states (even large ISPs) that can do that. Also, the first thing to go in case of global conflict is the global Internet. Countries will t…
It's like a USB stick but it stores inside a Bitcoin private key that's not revealed to the user unless they visibly break a part of the stick. This basically allows you to "load" bitcoins on the stick and give to others while being relatively certain of the "transaction" while of course being offline.
I assume it's probably possible in theory that with an electronic microscope or something similar a skilled engineer will be able to read that private key, but I haven't read of any reports that it has happened yet, but it all depends on the value contained to make it worth the effort and even then we won't know.
This basically allows off-chain & off-internet transacting which is really cool and enables the use in some more cases.
Personally I know that Bitcoin is not perfect, it has strengths and weaknesses but it's good enough for a lot of use-cases at the moment and it will keep getting better. There are quite a lot of talented engineers & cryptographers actively working on Bitcoin and cryptocurrencies that will move things forward quite a lot. Unlike Gold, Bitcoin can be upgraded to do more thing and evolve, be it Bitcoin or some other cryptocurrency, unless we live on an age of having govs ban a technology it will find its place on our daily lives.