So that when you are leaning over the sink, shaking salt on your freshly hard-boiled local egg from the farmers market, you will be able to see the dead ant before you shake the salt on said egg.
Or as in my case, after eating an egg and a half you bother to investigate that darkish spot you've been seeing out of the corner of your eye each time you tip the shaker.
Oh well, finish your egg. They were the best tasting hard-boiled eggs you've ever had, and you can't let them go to waste.
After all, a dead ant in the salt is nowhere near as traumatic as an earwig in the mouthwash. That you may never recover from.