Steel Man Argument for Fiat

Perhaps this is the wrong group to ask, but I'm having a discussion with a friend and he's skeptical of Bitcoin and has high trust in the government and fiat currency. One of his arguments is that under a Bitcoin standard, how is a government to effectively and quickly address emergencies like natural disasters or wars? What if a fiat nation was at war with a Bitcoin nation, wouldn't the fiat nation be able to make more arms for a longer period and therefore be better at war?

Curious about your thoughts on this and other arguments to steel man a fiat standard.

Thanks.