The point, which regrettably you missed, wasn't the (stat etc)[n] idiom. It's the use of _ as an argument to these operations to reuse the cached results of the last one.
Comment on Re^6: Counting bytes in a Unicode document
I used "_" in the post to which you replied. How could I have missed a point you didn't actually make? Like I said, your version ((stat(_))[7]) is—in my opinion—strictly worse than what I posted (-s _).