Ok, imagine you have an alarm-clock with radio function. You normally have a switch with 3 states: “on”, “off”, “auto”. Else get a fan with heating, you normally have a switch with something like “off”, “cold”, “low heating”, “high heating”.
It would be nice to have a switch on the dashboard which has more than 2 states.
Closing as a duplicate. Please search before posting. You can vote and comment here: Three-position switch with "ON," "OFF," and "AUTO"