$entity_wrapper->save(true) vs. entity_save('node', $entity)? Say I've got the following block of code:

$language = language_default();
$values = array([...]);

$entity = entity_create('node', $values);
$entity_wrapper = entity_metadata_wrapper('node', $entity);

$container = entity_create('field_collection_item', array('field_name' =&gt; 'field_container'));
$container-&gt;setHostEntity('node', $entity, $language);
$container_wrapper-&gt;save();
$entity_wrapper-&gt;save(true);
entity_save('node', $entity);


The above block of code invokes three different save() methods. Is this strictly necessary? Does entity_save cascade to $container_wrapper->save() and $entity_wrapper->save() if I do not explicitly call these? Are all three necessary? 

Things appear to work find if I skip $entity_wrapper->save(true)...but am I missing something?
You need just one save call. All of them invoke the same code, the controller's save method (or node_save in node's case).

The wrapper modifies the original entity by reference, so it doesn't need an explicit save of its own (and the other way around).