So basically "NextDoor: Fediverse Edition".
I'm not against but I think uptake will be difficult because, depending on your starting region you may be competing with an established product and because there is a heavy venn overlap between people who care about decentralization and those who care about privacy and wouldn't want an app tracking and to some degree giving away their location.
(Clarity Edit: I have a cold, my ending was guessable , but technically gibberish.)