Laravel Loading Service Provider and Alias

Maybe it is just me but im not sure what this do and why they need to do this?

in the providers that are loaded in laravel they did this

'providers' => [

        /*
         * Laravel Framework Service Providers...
         */
        Illuminate\Auth\AuthServiceProvider::class,
        Illuminate\Broadcasting\BroadcastServiceProvider::class,

...

same for alias

'aliases' => [

        'App' => Illuminate\Support\Facades\App::class,
        'Artisan' => Illuminate\Support\Facades\Artisan::class,

...

What does the ::class do and why can't they just leave it off like this?

'aliases' => [

        'App' => Illuminate\Support\Facades\App,
        'Artisan' => Illuminate\Support\Facades\Artisan,

via Chebli Mohamed