We have had smart meters for a few years now. The only use they have been is that someone downstairs can see, by looking at the load on the electricity on the remote display unit, that another person is using the electric shower. This prevents you from filling a kettle, flushing the downstairs loo etc, thereby giving the showering person a taste of hot water from the shower due to water pressure drop. Our shower doesn't have temperature stabilisation.
As for saving you anything, forget it.