There must be a reason why. Not a physical reason, but one involving style or artistry. It creates a more compact character shape, implying tension. Better than just plain landing on your feet. This nifty video was edited by Duncan Robson, with music by Joel Robson. It was first shown at ROFLCon III, a con I've never heard of, and why not?
Thanks to reader Chris Swanson for the link.