为什么要使用简写语法声明/初始化变量？

Question

Is there a difference between these 2 styles of variable declaration/initialization?

package main

import "fmt"

func main() {

    var a = "I am a string"        // Declare + init (infer)
    fmt.Println(a)

    b := "I am a string"           // Declare + init (shorthand)
    fmt.Println(b)
}

I fail to see the added value of the shorthand syntax, and inclined to use the "var" statement for consistency throughout my code.

Answer 1

I only use var when necessary, like:

1) global variables

2) if statement like:

var err error
if x == nil {
    err = errors.New("x is nil")
} else if y == nil {
    err = errors.New("y is nil")
}

...