My wife and I both WFH.
The Ecobee sensors let us manage the temperature in the house based on our locations.

For example:
Our upstairs Ecobee is currently set to 76, but if it detects somebody upstairs it will drop to 74.

Our bedroom is always Hot (summer) or Cold (winter) due to the location and large windows. With the sensors, it will average out the readings and keep the bedroom at the target temperature at night.

If you turn on our fireplace in the center of the house, without the sensors the 'outside' rooms get cold in the winter. With the sensors, the fireplace doesn't affect our main floor.

i could go on... (it works as an Alexa or Siri device, the nice app graphs that compare your house to others in your area.. etc). But basically, it just gives ME (not the utility company) more control over how i want my house 🙂

PS. The Nest has the same type of sensors, i just hate the Nest UI.