I'd say that with different hourly prices, I need a way to turn on and off some appliances when the electricity price is inside different ranges. But I will not spend my day having a look at my phone every 15 minutes.
Beside, that sort of automation has been available for decades, way before smart meters. My parents have been running like that for 20 plus years: the electricity would be at a reduced fee all the year long except during day time on 9 (or maybe 20 ?) days that are deemed to be very high demand (like the coldest of winter), if you used any electricity during those high price days, it was high priced, really (3 times the normal price comes to my mind). The days are not fixed in advance. So it was up to you to monitor if you were in a high price time.
And only running analog meter, the power company could send a signal (multiplexed into to 50 Hertz?) that you could use to automatically turn off stuff (electric cooker, over, electric water heater (they keep the water warm enough for 10 hours when they have proper insulation), washing machines, etc.) and turn on some signal light to remind people in the house.
I always visited during summer, so I never saw the system in use except the last time in Marsh 2019 when I went down to the kitchen one morning to be greeted by the red light.