Does destroy need to use both this.element and this.widget()?

jquery.ui.widget.js

...
$.Widget.prototype = {
    ...
    destroy: function() {
        this.element
            .unbind( "." + this.widgetName )
            .removeData( this.widgetName );
        this.widget()
            .unbind( "." + this.widgetName )
            .removeAttr( "aria-disabled" )
            .removeClass(
                this.widgetBaseClass + "-disabled " +
                "ui-state-disabled" );
    },

    widget: function() {
        return this.element;
    },
}
....