Sprints are a race to get work done in a smaller period of time. We’re not rushing to get work done, hopefully, we’re taking on just what we can, but the word itself is a sprint – so we are trying to get it all done.
Farming on the other hand, is slow, meticulous, and planned out by pre-determined steps that take a period of time to accomplish. You can’t demonstrate farming at the end of two weeks to show how far you’ve come, because sometimes you can’t see it.
You don’t always have to have an end demo for a sprint, but you do have to show progress.
The difference is that in farming we implicitly trust the process, so we know things will happen, in Sprints, we’re still trying to get to that baseline.