This sounds like a real organic way to create a follow list from your initial interactions.
I also think in some way, some kind of onboarding mechanism that allows you to want to find people to follow who are geographically closer to you would be really cool. Making it easy to create a “Barcelona nostr thread”. But i can imagine this would need to be an “opt-in” kind of option so people can remain geographically-private if they want to.