Both discretionary and system trading offer unique and selective benefits. One of the advantages that discretionary trading offers is the ability to adapt to changing market conditions. Trading tactics can be more relevant to the current market conditions at the cost of greater uncertainty (less confidence). On the other hand, trading systems are typically verified against many years of data increasing confidence at the cost of relevance.
Developing trading systems with shorter histories based on ideas derived from current markets may offer an attractive blend of both confidence and relevance compared to the alternatives.