Normally walkability also correlates with density of both businesses and houses which also encourages people to live closer to where they work. Compare that to a business park in the middle of the suburbs which requires a long distance commute to reach it.
> For instance, two year olds.
Probably easier to push a child on a stroller through a walkable area than to put it in a car and drive to a location. Less time-consuming and better for the environment as well.
As well as walkable spaces being better for the elderly who can't legally drive and the handicapped who can't legally drive as well.