Why is IP required, and even if you used IP for transport why must the
meter identification be based on an IP address? If meters only report
information, they don't need a unique transport address and could put
the meter identifier in the application data.

Even if the intent is to include additional controls, e.g. cycle air
conditioners during peak periods, you still don't need to use IP or
unique IP transport addresses.

Just because you have the hammer called IP, doesn't mean you must use
it on everything.

Exactly. A meter should be able to connect over an available transport method, and be identifiable via a serial number, not an IP. It may need to grab a DHCP address of some sort (or whatever the moniker is for the transport available), but in the end it's unique serial number should be used to identify itself.