c# 3.0 - C#3.0 Automatic properties, why not access the field directly?

Question

With the new approach of having the get/set within the attribut of the class like that :

public string FirstName {
        get; set;
    }

Why simply not simply put the attribute FirstName public without accessor?

Answer 1

Two of the big problems with direct access to variable inside class (field/attribute) are:

1) You can't easily databind against fields.

2) If you expose public fields from your classes you can't later change them to properties (for example: to add validation logic to the setters)