Angular ui-router: ui-views vs directives?

Question

The angular ui-router allows multiple nested views. The role of these interchangeable views seems to overlap the role of directives.

What are the pros/cons

Answer 1

It seems you can do something like this with relative impunity:

    $stateProvider.state('general', {
        url: '/general',
        views: {
            main: {
                template: ''
            }
        }
    });