They explicitly mentioned in the keynote that they are closing a couple of loopholes used for tracking including browsing for nearby bluetooth and wifi networks

They explicitly mentioned in the keynote that they are closing a couple of loopholes used for tracking including browsing for nearby bluetooth and wifi networks instead of actually requesting your location with the location API. You can now also approve location requests each time they occur, instead of having to allow them always/when using app. I imagine this is exactly why.