We resisted a smart meter for years until they told us our meter was past its allotted date (true) and could have conked out at any moment (possibly true, but it's really just an abstract possibility, not a hard fact). Octopus told us they don't install the older style of meter, which was what tipped the balance for us, as they would have charged a fee for an emergency change-over. Anyway, we finally gave in and had a smart meter installed (free of charge). Since then, we've noticed no difference at all, except we now don't have to take a physical reading and report it online (which took about 4 minutes - whoopee, however will we spend the free time saved every month?).
I've never believed the nonsense about a smart meter saving us money. We don't need to have instant access to our meter in order to think about how much electricity we're using and where we could cut down! That's just normal adult behaviour in real life.
Smart meters do, however, save the electricity companies a lot of money, since they don't have to employ meter-readers. This is a big part of the reason why they have been pushing smart meters at use as though they're the answer to eternal life, health and happiness - we still have to pay for what we use, just as before, but it costs them a lot less now to find out how much we owe them. The final bill amount is still our responsibility to manage and they will still cut us off if we don't pay...