Momentum capture.
RSI is used by traders and investors to help identify potential buy and sell signals in financial markets.
People use RSI for
~ Identifying overbought and oversold conditions
~Confirming trend strength - this is what we used and it gives very high returns , approx 2.5 times the market returns when the price is increasing but performes not that good while price goes down as RSI might not have been able to confirm the downtrend sometimes.
~ Finding divergences - can be used to find divergences between the indicator and the asset price, which can be a signal of a potential trend reversal.
~ Generating buy and sell signals - As we know , RSI below 30 is oversold region and RSI above 70 is overbought region , so this might give an indication of what trades to take.

The above listed includes some of the ways in which RSI makes life of a trader or even an amateur investor simple.