There are two main aspects.

One is long-term food security - even if global trade is mostly fine right now despite the current hiccups, there's no telling how it's going to be in a decade or two, and it's hard to ramp up production (due to lack of skillset, machinery and infrastructure) if you suddenly need it; so it makes all sense to pay some fraction of a percent of your GDP to ensure long-term strategic security of your food supply, especially if it looks like global tensions will eventually rise due to climate change.

The second aspect is that even in the current circumstances we're seeing rapid urbanization and depopulation of the countryside, which is generally seen as a problem for many areas. In a "natural" regime without rural subsidies this would happen even faster.

So many reasons why this is bad, but the most obvious reason right now is the supply chain crisis. It’s one thing if you can’t get a new car. It’s another if you can’t get new food.

Relying on imports for food makes your country a sitting duck in times of war. All the enemy needs to do is blockade you and then you can be starved into submission.

Given the global logistics mess at the moment, I would think it's pretty obvious why the location of food production matters.

States know very well that any given civilization is about nine meals away from anarchy.