The theory is they can also that they can do more sophisticated pricing. Historically there was the Economy7 (and slight variants) that allowed them to charge less for night time power when demand was less but with updates every 30 minutes they could actually vary costs by time, day, month etc. I’m sure I saw an advert for one company that did a 20% off or something for their smart meter users for a weekend or such which is something that could never be done with a traditional meter.
Will it work in your favour? Depends on your usage habits -v- peak periods. The headline is it’ll reduce energy useage by ~2.5% but the other theory is it’ll help level demand/ reduce the peaks/troughs
Personally, our meter is in a communal cupboard with others on the floor. The freeholders fear people bypassing the meter or patching into a neighbours supply and so we have to get concierge to lend you the key which you must then return within the hour. It can be a pain and so a smart meter would be good for us because 80% of our bills are estimates