privacy is a concern
These things operate on a mesh network. If my meter is not able to contact a cell directly, it will pass my information through a nearby meter, which forwards it further, either to a cell (if it has access) or on to other meters as needed.
It is possible to crack the data, which would give someone very detailed information about your comings and goings. In fact one could determine when you AND your neighbor are out, providing an ideal time to break into your home from the direction of that neighbor's house. No witnesses.
There's more, I suggest you look into the capabilities of IPv6 and this concept of "an internet of things." Don't forget to factor human nature into your pondering. If something has a potentially evil use, it is guaranteed that it will be put to that use. (in many cases the anti-social application is the FIRST use of a given technology, think nuclear fission)
I taught computer sciences for a brief time, and often found discussions concluding with "just because we can doesn't mean we should." I'm not particularly thrilled with the total surveillance grid the statists are erecting all around us.
"Smart meters" do not need some of the capabilities they are endowed with in order to be "smart," that is to do the job that is claimed of them.
