Laravel 源码 Collection（集合）请教

Collection.php

/**
 * @property-read HigherOrderCollectionProxy $average
 * @property-read HigherOrderCollectionProxy $avg
 * @property-read HigherOrderCollectionProxy $contains
 * @property-read HigherOrderCollectionProxy $each
 * @property-read HigherOrderCollectionProxy $every
 * @property-read HigherOrderCollectionProxy $filter
 * @property-read HigherOrderCollectionProxy $first
 * @property-read HigherOrderCollectionProxy $flatMap
 * @property-read HigherOrderCollectionProxy $groupBy
 * @property-read HigherOrderCollectionProxy $keyBy
 * @property-read HigherOrderCollectionProxy $map
 * @property-read HigherOrderCollectionProxy $max
 * @property-read HigherOrderCollectionProxy $min
 * @property-read HigherOrderCollectionProxy $partition
 * @property-read HigherOrderCollectionProxy $reject
 * @property-read HigherOrderCollectionProxy $sortBy
 * @property-read HigherOrderCollectionProxy $sortByDesc
 * @property-read HigherOrderCollectionProxy $sum
 * @property-read HigherOrderCollectionProxy $unique
 *
 * Class Collection
 */

    /**
     * The methods that can be proxied.
     *
     * @var array
     */
    protected static $proxies = [
        'average', 'avg', 'contains', 'each', 'every', 'filter', 'first',
        'flatMap', 'groupBy', 'keyBy', 'map', 'max', 'min', 'partition',
        'reject', 'sortBy', 'sortByDesc', 'sum', 'unique',
    ];

    /**
     * Dynamically access collection proxies.
     *
     * @param  string  $key
     * @return mixed
     *
     * @throws \Exception
     */
    public function __get($key)
    {
        if (! in_array($key, static::$proxies)) {
            throw new Exception("Property [{$key}] does not exist on this collection instance.");
        }

        return new HigherOrderCollectionProxy($this, $key);
    }

HigherOrderCollectionProxy.php

    /**
     * Create a new proxy instance.
     *
     * @param  \Illuminate\Support\Collection  $collection
     * @param  string  $method
     * @return void
     */
    public function __construct(Collection $collection, $method)
    {
        $this->method = $method;
        $this->collection = $collection;
    }

    /**
     * Proxy accessing an attribute onto the collection items.
     *
     * @param  string  $key
     * @return mixed
     */
    public function __get($key)
    {
        return $this->collection->{$this->method}(function ($value) use ($key) {
            return is_array($value) ? $value[$key] : $value->{$key};
        });
    }

    /**
     * Proxy a method call onto the collection items.
     *
     * @param  string  $method
     * @param  array  $parameters
     * @return mixed
     */
    public function __call($method, $parameters)
    {
        return $this->collection->{$this->method}(function ($value) use ($method, $parameters) {
            return $value->{$method}(...$parameters);
        });
    }

我的问题是这里为什么要用 HigherOrderCollectionProxy 来代理，有什么好处？这些方法都是 public 形式的，直接调用方法不好吗？