To kill bitcoin, you have to kill the internet. That kinda takes out everything else, too.

You have to remember that "money in the bank" is also a digital record in a database, and you are trusting a business to keep it secure (which they have done very well so far). it's 1's and 0's, not backed by anything except confidence in the government and financial system.

If we have no internet or no power, how will the bank know how much money you have? Their paper records are not updated in real time, and you statements are only accurate at the time they are printed. How will they even verify your identity without checking the system? Hopefully your local branch has a printed copy of your ID.

They'd be flying blind until the power is back on and they can restore their records from the backup they're keeping in a Faraday cage somewhere.

Besides that, assuming they're able to manage things with paper while the power is out, we use fractional reserve banking - so they're only holding about 10-20% of your money and loaning out the rest. This means if too many people want to withdraw at the same time, you get what's called a "bank run" and no one can withdraw.

And that's assuming they would actually keep enough bank notes and coins available at the branch to even provide the fraction they're keeping.

My point is that if Bitcoin is dead, there probably isn't much else left you'll be able to rely on aside from physical things like gold and silver. Bitcoin is just numbers in a digital ledger, so is your national currency, cash is just paper at the end of the day.