Several energy companies tried to get us to install them (we tended to switch suppliers each year back in those days) but when we mentioned that we had solar panels they suddenly were less interested stating that their meters were not solar compatible. "smart" .... mmm .... more like "dumb".
We still don't have one and I don't miss it.
Many years ago I bought an instantaneous energy indicator. It was a simple current clamp attached to the incoming live. It was never very accurate and totally hopeless once we installed solar because it didn't sense the voltage potential or measure solar export so was never a true measure of power. The thing was though, it was quite big and very obvious and it was clear when, for example, I'd accidentally left the coffee machine turned on. That, to me, was far better than something which integrated over a long period and gave a number that was quite difficult to read or learn from.
In more recent years, once we got solar, I built a load of microcontroller based modules and wrote the code to properly measure instantaneous load, be it import or export. Nice big LED's told me, at a glance, if we were importing or exporting and I calibrated the whole thing to within a couple percent of the actual load that the house was taking (or contributing to the grid). I also built an immersion heater bypass so that surplus solar power could be dumped to the immersion heater, cycle by cycle while still receiving money for the export (yes, it is legal). The system just sits there, the instantaneous import or export being displayed every ten seconds or so and I get hot water when the sun shines.
Smart meters don't save money for most people. It's a way for companies to grab more analytical information about us and to consign house to house meter readers to the dole queue. If you want to know how much an appliance is using, plug it into a something like this instead
Power Meter Dual Tariffs with Backup Battery, Maxcio 13A Electricity Usage Monitor UK Plug for Costs Voltage Amps Watt KWH, Large LCD Display Watt Volt Amp Analyzer for Home Appliances, No Backlight : Amazon.co.uk: DIY & Tools
Where a visual indicator does help is to change habits. It's the big resistive heaters which most consume power and if something can tell you that you left one of these on, that's a smart enough use of technology to save most consumers some money, if they can be bothered.