why am i doing cardio??

dont need to worry about making weight. i would like to be 231 or under to qualify for nationals as a lightweight, but why? i have 6lbs to lose. most of that is water....only problem....dont think i will make early weigh ins. so i if i do i will be dehydrated saturday morning. good for me the comp starts at noon. its possible but i am not worried. just going to have fun!