Actually in case of that what you need is food and shelter because neither fiat nor bitcoin are going to prevent starvation or stop bullets.
Not to mention that you can't really store large bags of cash in your home because the banking system is going to be the first that will get hit. You can see how Russia performed a large scale cyber warfare against Ukraine over the past couple of days that included hacking their banking system. Meanwhile bitcoin is not and can not be affected by this.