What does the "Pivot" button above Scene View do?

Unity Engine
1

What is this for? It’s visible in the screenshots for the interface tutorials, but never described what it’s for or how it would make my life better.

2

If it isn’t pressed, then all objects pivot point will be in the center of it’s polygon’s. But if it is pressed then all objects pivot point will be where they were in their 3d app.

3

Oh, thanks, I see that now!