Nowadays, apps use device locations to provide a wide variety of services. You may want to see a user's location to show services around them, learn the habits of users in different areas, or perform location-based actions, like a ride-hailing app calculating travel distance and trip fare.
In order to protect user privacy, however, most apps request device location only when they run in the foreground. Once switched to the background, or even with the device screen turned off, apps are usually not allowed to request device location. As a result, they cannot record the GPS track of a device, which negatively affects the user experience of core functions of many apps, such as ride-hailing, trip-sharing, and exercise, all of which need to track location in real time.