What problem does this address?

The goal is to allow a page to create a menu/list of posts of all the children page, sorted by menu_order.

The solution in PHP could something like this:

$args = array(
    'post_type'      => 'page',
    'posts_per_page' => -1,
    'post_parent'    => $parent_id,
    'orderby'        => 'menu_order',
    'order'          => 'ASC',
 );

$child_pages = new WP_Query( $args );

An issue with pages is there is no means to add additional tag or category information as another means of limiting what is returned by the query.

Possible this should just be added to: #24934