I am new to wordpress and following a tutorial to create a new widget. I have noticed in some situations $instance variable is used and some situations $this is used. Like
$instance['title'] $this->get_field_id( 'title' )
I know first line returns the title value and second line returns the id of the field. But ins't $this means the instantiated object of the class? Why do I have to use $instance variable too? Can't we use $this to get title value of widget?