Latest O’Leary stunt a waste of space

I am rather confused about O’Leary’s latest stunt. His aircraft were obviously designed as passenger-luggage combies — passengers on top and luggage below. What happens to all of that wasted space below deck?

Surely O’Leary should be ashamed of burning millions of litres of fuel on a regular basis carting around untold cubic metres of fresh air?

I wonder what the proportion is between hand and hold luggage on conventional airlines, as opposed to O’Leary’s pack ’em in set-up?