Derivative trading is a sort of Forex hedging. You get the returns in money or stocks based on your performance over a period. There are futures and options to get the prices locked where you can do assured trading.
Thus it is a less risky trading option. They are best when done in mutual stocks as cumulative counting on a fixed price is bound to get positive results. Losses are due only during sharply volatile times.
The other reason is that you get the returns pretty fast in periods ranging from days to months. This is better for people who do not have the financial impetus to lock money for greater periods. Derivative trading may be done in share trading, Forex trading or mutual funds.
The third and probably the most effective reason is its tremendous flexibility. It lends credibility in many avenues. You can also take use of a financial authority.