The help text is not displayed when using the Inline Entity Form widget

This is intentional (Bojhan's design).

For anyone who comes across this and still wants some help text, I added some to my Inline Entity Form by using the instructions at http://drupal.org/node/1880850 and rewriting the $form['field_my_ief_field']['und']['#description'] value. My field is "Location" and my node type is "Hardware" so my full form alter code:

function mymodule_form_alter(&$form, $form_state, $form_id) {
  switch ($form_id) {
    case 'hardware_node_form':
    dsm($form['field_location']['und']);
      $form['field_location']['und']['#description'] = str_replace('nodes.', 'locations. My help text...".', $form['field_location']['und']['#description'] );
      $form['field_location']['und']['actions']['ief_add']['#value'] = t('Add a new location');
      $form['field_location']['und']['form']['#title'] = t('Add a new location');
      $form['field_location']['und']['form']['actions']['ief_add_save']['#value'] = t('Add this location');
      break;
  }

May I ask why this is intentional?

Because help text adds visual noise.
However, I'm fine with adding back that possibility, if you don't feel it's noisy, you should be able to set the help text (while we in Kickstart won't).
Closing for #1992434: Widget form does not expose admin-entered help text since that issue is more detailed.