" And there are many more flaws than just the ones you could be bothered to mention."
Separate pressure vessels and the weight penalties associated with them being the first thing that springs to mind, not to mention that in an engine-out situation a plane is still landable and pyros tend to be unreliable. On top of that, in order to make the tube capable of taking the loads in the video without bending you'd have to make it substantially stronger and therefore much heavier still. Would it get off the ground?
Even light aircraft whole-body parachute recovery systems come with penalties and haven't always saved lives