The Closed Trades Cumulative P&L shows your equity curve broken down by your disciplined trades versus your undisciplined trades.
Over time, and with enough closed trades, you can see how different your P&L would have been, if you have been 100% disciplined.
It is very common for disciplined trades to be profitable, and for undisciplined trades to be unprofitable. This chart lets you see the impact over time.
The Daily / Weekly / Monthly reviews are an opportunity to track your ongoing discipline, and for you to consider how well you are adhering to your trading rules.
Using these reviews will give you all the information you need to make decisions on your risk management, your money management and your trading strategy.