I see one of the early proponents of them has binned his: https://www.thetimes.co.uk/article/ex-m ... -0ntg3mb75
(paywall site, but you get the gist and can find it elsewhere)
I knew I'd never look at one, so never saw the point.
Stuff that needs to be on in my house, is on.
Stuff that doesn't need to be on, is off.
It's not rocket science.
...although (for the conspiracy theorists), every electrical device has a unique signature. So, if you're worried about being spied upon, the smart meter could be a wee spy in your camp.
Oh, and they don't work if you change supplier?
I change mine every two or three years (always a cheaper deal available), so that'll probably make them 'less' than useless, eh?