Re: Smart meter vs dual-tariff (Off Peak) meter ?
An old-fashioned dual-register meter has its peak and offpeak timing basically hard-wired, which means the definition of "peak" in your 40-year-old meter is now 40 years out of date.
Modern smart meters allow utilities to rewrite those definitions whenever they like, and also to introduce more categories ("shoulder" is a popular designation, also separate rates for weekends/public holidays that are neither "peak" nor "offpeak"), and also to monitor "demand" (i.e. the highest amount you ever draw in a given single half-hour), which is a big thing for them.
Not saying this is inherently good, just that the functionality is a lot greater.
Incidentally, they do also give cost savings even if you never change your electricity usage. It costs money to send a guy round to read a conventional meter every couple months, and that cost is multiplied manyfold if they have to make repeat visits, go out-of-hours etc (because no-one was there to let them in), then bill on estimates, with the added risk that entails... Smart meters put an end to all that, and they sharply reduce the cost of reading meters.
For comparison: in Victoria, Australia, where smart meters are now near-as-dammit universal, customers used to be charged about $25 to get a meter read when you move into a new house. Now the charge is about $5, which of course is still far more than it actually costs (approximately nothing, with a smart meter), but unarguably better for the consumer, and less error-prone.