If you don't mind walking around and manually turning things on and off, setting alarms and thermostats, etc., you don't need a home automation system like Control4. In a high end home, at least in techie areas, buyers expect automation these days, so it will likely affect resale value.
from my perspective, the real value is in scenes. For example, you can have a scene called good morning that turns up the heat, turns on your Tesla interior heat, opens blinds, turns on certain lights, turns off your security system, etc. Or a 'guests arrive' scene that turns on exterior lights, unlocks the front door, turns on a water feature in the entry, stairway lighting ... One that comes in very handy is to have a scene 'all off' next to your bed that turns off everything in the house that you want powered down and closes the bedroom blinds. Scenes are mostly limited by your imagination. Again, they don't do anything that you couldn't do manually, but in a big house it saves a lot of time.
My wife is a total technophobe and she really likes pushing one button that turns on her favorite music in whichever room she is currently in and another that turns on the TV, receiver, etc. so she doesn't have to figure out how to turn on music or TV manually.
I don't like Alexa for C4 voice control because of questionable security and its kludgy integration with Control4. Josh.ai is better, but pricey.