[betterunix2]

A number of ISPs have started using NAT for IPv4 due to the address space crunch, which means that at best those IPv4 addresses can only be used for coarse geolocation. The fact that IPv6 addresses are per-device means that at a minimum you can get household level geolocation for each device (based on the prefix). The fact that addresses are long-lived is not really relevant, since addresses are only long lived with respect to a prefix and prefixes will change when a device moves to a different network (almost always the case with residential service).