They are the precursor the the Smart Grid. Which is about encouraging/discouraging people to use electctricity are certain times by charging more/less. ie, when there is plenty of electricity, it will be cheap. When there is a dearth, it will be expensive.
Opportunity for the well informed to save money. Also they will conrol power exported from domestic PV panels/other renewable stuff.
It's comng whether you like it or not. Everyone will have one.