Why is it important for a router to have a metric for determining an optimal route?

What will be an ideal response?

The difficulty here is when multiple routes are available that compete to be the default route.There are different metrics for choosing a "best" connection, but the actual metric chosen is less important than having a functional route that is known by the router for making device-to-device connections efficiently.If no path is chosen, a consistent route cannot be determined, making network behavior erratic and leading to imbalanced traffic patterns.