> Geolocation based on IP address is always done in the background, so they already know what city you are from

They don't. Maybe the trackers do, but most websites place me 100km to the west. When I want to look up opening times for supermarkets near me, I like the "show nearby" button.

Even Google gets confused because I VPN back to my home network. Every time I spend a few days somewhere else, Google's IP-based geolocation is broken again.