It’s not just farmers. It’s useful for anything that involves future delivery of a good that could have a variable price or production.

A mining company would sell gold futures under the expectation that they will mine a known quantity of gold. They trade the risk of price fluctuations to match against their known liabilities (e.g. labor or depreciation of equipment costs).

Now replace “gold” with lithium (for electric car batteries) and you can create the greenwashed story that you want to hear.