They send real-time data on customer usage to suppliers remotely when in “smart mode”.
It said a poll carried out between August and October 2023 involving 4,000 domestic energy consumers across the UK showed that 20% of households with a smart meter still had to regularly submit manual meter readings because their device was not doing so automatically.
I usually spend effort trying to figure out how to prevent companies from having their devices upload data about me to be data-mined, so the concept of someone being upset about the opposite occurring is kind of novel.