I am not sure the question is not answered by one, but I'll elaborate just so we are clear. If you can find a block with an rPi ZERO then you'll agree the mBTC is covered by that block, or am I missing something here? Then again, I am not sure one rPi ZERO can not mine an mBTC and still be re-useable, be it for tinkering or as an expensive controller, and that in effect being the proof that cpu mining is not dead.
But you are right, you started this thread and you must be correct.