What does the 'Eco' button do in a Kia Rio?

I recently bought a Kia Rio and noticed there's an 'Eco' button on the dashboard. Can anyone explain what it does and whether I should be using it?

The 'Eco' button adjusts the car's engine and transmission to optimize fuel efficiency. It's recommended to use it when driving on highways or during long trips.

I never use the 'Eco' button in my Kia Rio and my gas mileage is still great. I think it's just a marketing gimmick.

I always use the 'Eco' button in my Kia Rio and have noticed a significant improvement in my gas mileage. Give it a try and see if it works for you.