I'm almost certainly not the first person to suggest this but could you use the ecash "stamp" model of nostr:nprofile1qqsth7fr42fyvpjl3rzqclvm7cwves8l8l8lqedgevhlfnamvgyg78spz4mhxue69uhhyetvv9ujuerpd46hxtnfduhszrnhwden5te0dehhxtnvdakz7qgawaehxw309ahx7um5wghxy6t5vdhkjmn9wgh8xmmrd9skctcygfl2f for geohash messages ONLY? Like imagine this:

-user downloads Bitchat

-onboarding is free

-friend next to them sends some ecash via BLE straight to built in wallet

-now user can branch out to geohashes

Is this retarded?