Why are Stop Lines (in the US, at least) often set too far back to see any crossing traffic?

I've seen them called "Stop Lines", "Balk Line", etc. The thick line painted on the road at a Stop Sign.

You're supposed to stop before the line, but a lot of the time there's a bush or other obstruction so you can't see any crossing traffic. You have to creep forward until you can see anything.

Is there a reason for this? Is it done on purpose? It makes sense if there's a crosswalk or something, but I see it a lot where there shouldn't be any pedestrian activity.