I have to say, I will never allow Monzo to use my location in the background for as long as it is uses GPS. Your location-based security is a great idea, but GPS kills battery. GPS really isn’t suited for 24/7 use. A better alternative would be to use Wi-Fi location and triangulation, like the Dark Sky weather app does. These methods are lighter on battery. The only reason I gave Dark Sky ‘Always’ permission for location was because of this on their website:
Dark Sky uses my location in the background when notifications are turned on. Won’t this drain my battery?
No, this will not drain your battery. Dark Sky does not use GPS, which can be a big battery hog, to get your location in the background. Rather, your phone will periodically find your location via Wi-Fi and cell tower triangulation, which doesn’t have an adverse effect on battery.