We observe that using the concept of the Hurst exponent can lead to very useful insights about the market regime. With that information in hand, one can decide which of the two strategies, mean reversion or momentum, is more appropriate to adopt.
In short, the value of the Hurst exponent identifies if the time series has some memory of past events. The fact that the value of the Hurst is not always equal to 1/2 shows that the efficient market hypothesis, according to which markets are completely unpredictable is often violated. Properly identifying such anomalies can in principle be extremely useful for building efficient trading strategies.