In all the talk of graphical downgrades no one seems much preoccupied with 'why?'. Why build something and then proceed to tear it down, piece by piece, in the hope that ever more diminished expectations about the final product won't be severe enough to...
You can move in the air, which is helpful when the arrows start flying.
Watch out for sharks coming up from underneath.
If you've had a power-up for a while, don't bank on it lasting much longer. Don't task the risk.