The usefulness of destructive

I want to know the real use constructors in PHP.
I found some classes in PHP with a destructor that destroys all the attributes of objects in the destructor with unset

class MyClass

private $object1, $object2, $object3;

public function __construct()
  $this->object1 = new ClassBB;
  $this->object2 = new SampleClass;
  $this->object3 = new Example;

// Content Class

public function __destruct()
  unset($this->object1, $this->object2, $this->object3);


Is that going it change something in performance of PHP?
Otherwise what is the destructor in PHP?

Thank you

If those classes were taken up big chunk of memory and are no longer needed then unsetting them will most likely improve performance. I don’t think there are other benefits.

It’s is completely unnecessary and make no difference.
The objects that are instance variables are going to be picked up by GC as soon as the object itself is destroyed by GC.