Derivatives are extremely valuable instruments, which is why there is so much effort dedicated to creating and trading with them. What they let you do is hedge against risks that previously could not be hedged against, and this in turn allows people to try things that were too risky to contemplate doing before the derivatives existed. I spent half a decade working at a company that was trying to roll out a new derivative product. The idea was that home loans usually represented the single largest source of financial risk to a given family. If you could buy insurance against sudden declines in the market, then you would not have to worry about potentially getting "trapped" in a bad job or bad neighborhood because of an unanticipated drop in property values. That's a new liberating potential made possible by a very sophisticated piece of financial design.
Sure, derivatives can be misused, but that's true of everything: the human capacity for fraud, self-delusion and stupidity long predates the Black-Scholes equation.