It seems like the current model of IP addresses does not assign each device an IP based on that device but rather, to the router, so your IP would change if you went to Starbucks; IP cannot be the only identifier then, for any application that requires a persistent identification, beyond location.<Turing>
References:
Realm Specific IP: Framework<2001>: https://datatracker.ietf.org/doc/html/rfc5128
Special-Use IPv4 Addresses<2002>: https://datatracker.ietf.org/doc/html/rfc3330
Privacy Extensions for Stateless Address Autoconfiguration in IPv6<2007>: https://datatracker.ietf.org/doc/html/rfc4941
https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/using-instance-addressing.html