tour: defer - a short description on a genuine use for `defer` may be helpful

[benkoshy]

Context: https://go.dev/tour/flowcontrol/12

Defer
A defer statement defers the execution of a function until the surrounding function returns.
The deferred call's arguments are evaluated immediately, but the function call is not executed until the surrounding function returns.

A brief explanation of why defering is necessary may be helpful. Because the example given seems contrived:

package main

import "fmt"

func main() {
	defer fmt.Println("world")

	fmt.Println("hello")
}

A tyro may ask: why not the following instead?

fmt.Println("hello")
fmt.Println("world")

i.e. in what scenario would defer be necessary? It seems that in every case I can think of - you could achieve the same outcome by ordering the execution differently.

my 2 cents.