The point of twisting them is to prevent them from pulling through the slots in the pedals. On most pedals, these straps are tight enough that they aren't going to slip. Do note that twisting them on pedals that are slightly smaller side to side will encourage some of the twisting tension to be transmitted past the pedal frame, making them more prone to hit the crankarms. Also, twisting takes up a couple centimeters of length and the better straps (being mostly Japanese, and made for a population with smaller feet) have gotten shorter in length than old European straps. You may not have those couple centimeters to spare.