What is the advantage of class autoloader?

Question

PHP

Simple code:

spl_autoload_register(function ($class) {
    include 'user/app/' . $class . '.php';
});
 
$obj  = new MyClass();
$obj->displayVar();

There are many classes in the user/app/ folder and the obvious advantage is that you don't have to include_once or require for each one. Those. we save a lot only on the time of interpreting files with classes, because even if we include them, but we don’t create an instance, then resources won’t be allocated to them anyway ... Is it
possible to get rid of the line and create an instance automatically at the moment ? Naturally in advance without creating "in reserve" on a copy of each class. $obj = new MyClass();$obj->displayVar();

Answer 1

after all, even if we connect them, but we don’t create an instance, then they still won’t be allocated resources ...

Resources are spent on the class declaration, functions (they need to be stored somewhere). The code is passed through a lexical analyzer, tokens are created for each token, and a syntax tree is built from the tokens. So, even just including a file consumes resources.
No.
In 2017, it's common to use composer for autoloading, rather than writing your own bikes.

Answer 2

no.

Answer 3

And you can get rid of the line $obj = new MyClass(); and instantiate automatically?

can

function __constuct(MyClass $obj){
$this->obj = $obj;
}

container.thephppleague.com/2.x/auto-wiring