Makes it easy to selectively clean up an area. Such as returning a coast line to pristine condition after getting a bit overzealous with the landfill. Also testing the edge case effects of a chunk being removed on nearby tiles and entities.
At least that's what I created it for almost a year ago. Finally decided to release it as part of my big 0.17 update.
Someone could also use it to refresh a specific ore patch if they were so inclined, but I would never do that myself more than twice.
