The country gets more resilient the more people stock up and try to be self reliant. This is the message put out by lots of different governments (eg: Sweden) Individually we benefit from having our own back up plans.
We, as a country are not self reliant for food. Haven't been for over a century. Having the means to grow your own/a stockpile to supplement rations, makes life more bearable. (Granddad had ferrets to catch rabbits)
We are more likely to suffer from hybrid war from our more traditional enemies. (Power cuts, infra structure being sabotaged, cyber attacks etc) Probably fuel shortages if a blockade.
Likely to have food shortages (like COVID with no pasta) or increase in prices depending on which countries go to war, where. (Fish imports if around Greenland, coffee, bananas, fruit from SA/Caribbean) Throw in a natural disaster or two. (Volcano, earthquake, hurricane) And other supply lines could be disrupted.
If Trump Invades Greenland we could be dragged into war. NATO would be weakened and we become an easier target for none NATO countries. China might take advantage of America being busy and persue some of their goals disrupting supply lines from Asia.
We can not stockpile enough to get through a whole war/nuclear winter but you can make life easier for the lesser disruptions.