Temperature and Humidity Sensors
Being able to measure the temperature and relative humidity is one of the most basic things you will want to do in a smart home. This metric can be useful in several ways: You can use the humidity to detect whether someone is in the bath or taking a shower, and thus keep the lights on even if the person is motionless. If you live in a dry area, you might turn on a humidifier when the humidity reaches a certain percentage, or you can use the temperature to adjust a thermostat. And some people, like me, just like seeing nice graphs on their Home Assistant dashboard.