You're bringing in a premise that, while is a law in itself, isn't actually comparable to the situation we're discussing.
He's let the ball hit the floor. Even if there was a bit of finger under it, there's not enough of it I think, and he's let the ball drag on the floor, clearly making contact.
There's people saying it evens out the Smith decision, so where does the even-ing out end?!
33.3 Making a catch
The act of making a catch shall start from the time when the ball first comes into contact with a fielder’s person and shall end when a fielder obtains complete control over both the ball and his/her own movement
That's the rules. So control of the body clearly isn't as useless or irrelevant as you make it out to be. Starc used his hands and the ball on the ground to control how he falls. So going back to your previous point, if he had to use his face to ensure it was a fair catch and eliminate all doubt, then do so...