One thing I've learned over the years is that this 100% depends on you and nobody's answer will really satisfy you, because the needs and routines of every individual can be radically different.

Do you care about energy consumption? If you do, you can pull in all that information into a dashboard, evaluate your usage patterns, and craft automations that ensure you're being as efficient as you want. Turn your lights/AC/music on and off when you go from room to room, etc.

Do you care about micro-optimizing your time usage? Create automations that support your daily routine. Tie your coffee maker's smart plug to the next upcoming alarm on your smartphone so you have breakfast ready by the time you get up. Have your garage door open automatically when it's time to go to work, and it's not a holiday, and your phone is at home, and your car is in the garage.

Do you care about eye strain? Have your smart lights change colour to match the light temperature of sunlight throughout the day.

Do you care about silly things that make you feel all powerful? Have your lights turn off, some white noise start, and all the smartphones in the house switch to Do Not Disturb when you plug in your phone to charge next to your bed after 10PM.

The sky is the limit. Over the years I've ping-ponged between "eh, this is not really worth it" and "this is actually incredibly convenient" depending on how my routine has changed.