Running a closure in the scope of an object took two steps: bindTo() to produce a new closure, then invoking it. call() does both, and it is considerably faster because no intermediate closure is created.
$reader = function () { return $this->privateTotal; };
// before
$bound = Closure::bind($reader, $order, Order::class);
$bound();
// now
$reader->call($order);The legitimate use is in tests and debugging tools that need to reach inside an object without widening its API. Reaching for it in application code is a signal that the class is hiding something its collaborators genuinely need, and the fix is a method rather than a binding trick.