Benches are perfect for defining public areas, an accurate placement of a bench can make or break a public zone.
Benches are places for human interaction, points of pivot, and moments of pause. They are perfect as destination markers for you to get to. Some are majestic, artistic and FUN.
I find benches to be a social-democratic piece of furniture that guide you through space, allow who ever wants to sit on, to enjoy it together with another person, or alone.