Arnold and Franco were both outstanding young PowerLifters before becoming professional BB's. When you consider the amount of muscles that get worked from the 3 exercises (Franco was a very good Olympic lifter too) then its little surprise the excellent base they had. I'd recommend any athlete, no matter what his sport, to include Powerlifting exercises in his program.
I compete in a weight category, but ever for those in the open category, I see no excuse for being out of condition. Why eat sloppy when you can just as easily eat clean, get in all your calories and look/feel great as well as strong?
I plan on one very heavy schedule next year in terms of competitions where I will compete in several meets. Used to BB before, but much prefer PL. Not as big, but way better defined and athletic looking. Many BB tell me they are sick of BB as the results are not very tangible if you don't compete, but in PL you always have Personal Bests to keep you focused and motivated whether you are a serious competitor or just do it for the enormous amount of personal satisfaction and benefits it brings.