Chart based online trading is or would be simple in that -
From on any candlestick or bar, based on the price movement that followed, It’s easy to say - I would have liked to have entered there, and exited or stop and reversed there for a profit.
So all chart users are capable of easily seeing what should have been done after it has happened.
But being able to do this in live trading by predicting future price movement accurately often and consistently enough, is EXTREMELY difficult. All within the confines of a necessary (as we do not know where price will move to or when) stop loss to prevent an account balance wipe out.