it is indeed a very good question and reminds me of my days in School where we used to debate on the topic: 'Is Science a Boon or a Bane?".
This question is on very similar lines. Derivatives can indeed help an ecomony to benefit from it if used correctly.
But the trend is more towards creating exotic products to generate profit out of it rather than using it to hedge against risk.
As Jeffrey rightly pointed out, hedge funds are a classic example of how they use dervivatives to reap profits for an individuals. Fund of Funds is another example where Fund of Fund manager invests in multiple hedge fund portfolio to ensure he gets the profits out of all the hedge funds and if he incurs a loss it its limited to an investment made towards a particular portfolio if hedge fund.
Speculators using derivatives are important too, because they provide liquidity to the market. You definitely need market makers. In traditional derivative markets, if you have the need to hedge an exposure, you can go to a bank and ask them to structure a derivative product. You can't do that with bitcoins.
