(1) variety across regions; (2) variety across seasons; (3) harder to scale up, and therefore less likely to be refined/processed/unnatural; (4) forces people to be creative about food, which adds to the culture.

Of course, those might not be true, but they are plausible enough to be attractive reasons.

One might argue that, technically, importing strictly increases options, and therefore makes it easier for an individual to eat a wide variety. But it also makes it easier for someone to get a little too comfortable eating exactly the same things for too long without thinking.