"This app may use your location even when it isn't open, which can decrease battery life."
why does it need my location?
You don't have to provide it if you don't want to, but there is a special device file (/dev/location) that can provide you with your location in real-time for scripting use.
but "even when it isn't open"?
makes little sense to me.
Because it can run in the background and you might write some code which uses it in the background