I see little value in having a function that tells me how many objects
of any kind I have instantiated. Mostly, I see it as a way to help
teach people about assignment of objects works in PHP:
$a = new MyClass();
$b = $a;
var_dump(get_object_count());
And that's about the sum of how useful I think this is.
If it were to be able to narrow it to a specific class then it *might*
be a little more useful.