Why do we need Random numbers in our code?

What's the purpose of the random number code in a real-life program? given below is a go program

package main
    import(
        "fmt"
        "math/rand"
        "time"
    )

    func random(min, max int) int {
        rand.Seed(time.Now().Unix())
        return rand.Intn(max - min) + min
    }

    func main() {
        myrand := random(1, 6)
        fmt.Println(myrand)
    }