The reason why crypto is mostly valuable during war is you can transact any place without the need to go bank, and of course during war banks are being short down and you can't access your funds during war so the only alternative is through cryptocurrency provided you have internet access and have mobile phone makes it more easier to transacts without having to seek permission from third party.
Banks cannot also function during wars so most likely, those who aim to withdraw their funds might be in trouble, even ATM machines funds will also be used up once banks cannot function properly.
However, with crypto, as long as there's still electricity and internet connection, doing crypto transactions will be hassle free. That's one of the advantages of crypto, while fiat banks might declare closure and depositors will be in trouble, those who prefer owning crypto will never struggle when it comes to deposits and withdrawals transactions.