"savings would be from not having to send engineers out to read meters"
You don't need an engineer to read a meter. I can get someone to drive to my house, pick up a parcel, transport it half way across the country where it is driven to someone else's house and delivered for less than 3 quid.
Just how much do you think it ought to cost to have someone read a meter a couple of times a year? Especially if they got their shit together tried to read them all at the same time.
Savings could come from dynamic electricity pricing to reduce peak demand and better match demand to supply but I am not convinced the current generation of meters are capable of supporting that and we don't have smart appliances and the rest of the infrastructure required to implement it painlessly.
There is no such saving possible for gas supply and that they are trying to force smart gas meters on people tells you it was never about efficiency or saving. It was always about forcing consumers to install real time guilt displays (at their own expense).
Biting the hand that feeds IT
