c# 3.0 - Difference between Automatic Properties and public field in C# 3.0

Question

I failed to understand why auto implemented property language feature exist in C# 3.0.

What the difference it is making when you say

public string FirstName;

than

public string FirstName { get; set; }

Answer 1

Because they are implemented differently in the resulting IL code (and machine language). An Automatic property is still exposed as a public getter and setter, whereas a public field is just that - a single field..

Thus, implementing an auto property allows you at some later date to change the internal behavior of either the getter or setter (like adding a validator) without recompiling or re=coding any dependant classes that use it...