Just saying supplements are useful for bodybuilders is meaningless.
What supplements, for what reasons, why are they needed to be supplemented, are they proven to work.
Best supp to spend money on for bodybuilders is vitamin s. The rest you need food, hard work and genetics. If you think the latest glossy bottled supplement stack is significantly contributing to your gains at least you are spending money helping and helping the economy.
I've said it before but supps are for those too scared to get on the gear and use something that actually works.