knee wraps offer no protection for the knees. The patella tendon will not move quite as needed with the wrap on. In powerlifting there is a greater chance of the lifter getting hurt while wearing wraps.
knee sleves are a much better option for knee health. apt makes some great ones ive heard.
that being said - i do use them as i compete, i use apt strangulators and get about 75lbs out of them