Why is it not possible to call a function like this
$this->getCollection()->getSku();
And it's possible to do it with a foreach like this
foreach($this->getCollection() as $item)
$item -> getSku();
endforeach
For reference ... ( in the block folder )
public function getCollection()
{
$model = $this->_objectManager->create('Ming\Test\Model\Test');
$collection = $model->getCollection();
return $collection;
}