I'm not sure automation has saved much money with the exception of my presence-detecting thermostat. Lights and such make up a very small percentage of my electricity bill to be honest as I have all LED bulbs everywhere. Certainly there's a cost in the initial investment, but given how long they last, it's just a matter of time until they pay for themseleves. But as it's only $0.50 per year per light if I leave them on 24/7, it'll take a while.
As for automation, I view it more as a security measure. Outside lights coming on before sundown and turning off at sunrise - don't have to remember to turn on/off and don't have to worry when on vacation. Same with certain inside lights - can give the impression that someone is home even when not.
Voice control of out lights is certainly convenient, however. Yes, it's easy enough to get up off one's butt to turn off a light. But it's nice to be able to just ask Siri/Alexa to "turn off the downstairs lights" when I'm on my way to bed.
My big electricity users are things one can't really automate - washer/dryer, refrigerator and water heater (yes, there are some options for water heaters, but as there are usually four or five persons living in the house at any one time, there's not much of an opportunity to shut the water heater down for any significant amount of time).
The thermostat is the main one that can be managed, and of course there's tons of options in that regard.