Missing billing information pane

I have two workflows, one does not require payment and the other does. But... Commerce payment removes the billing information pane.

/**
 * Implements hook_commerce_checkout_pane_info_alter().
 */
function commerce_payment_commerce_checkout_pane_info_alter(&$definitions) {
  // The payment_information pane replaces the billing_information one.
  unset($definitions['billing_information']);
}