Park opening/closing times?

I'm not sure which forum this should go in, so please feel free to move it to the correct one if this isn't right.

Genuine question - why is it that some parks close at dusk, while others remain open all night? I live right next to Downhills Park which is open through the night and I was wondering why. I know of parks several times the size of it that close at dusk, so I'm sure it's not an issue of being unable to clear the park before closing. However, I'm curious to understand the benefits of leaving it open at night because there isn't really any lighting, so it can't really even be used as a shortcut to the surrounding roads or anything (not that I'd particularly want to take shortcuts at that time!)

Is it simply for financial reasons, or is there something I've overlooked? I'd love to know the answer.