Probably journaling that he meant is that to have a gameplan, it is the way to monitor the market and record the previous history that will probably repeat itself in the future. If that is what OP means, it really has great help to him, and stick to the plan will most likely always get a profit because you can able to control your emotion. If you have a plan you will have an idea of when the exit point, when to take profit, and when you leave the market. There are too many advantages to be made if you have journaling everything the decision you have.
I think if you could keep track of everything, it would probably help, or at least it probably can't hurt so you could do it and if it doesn't help it doesn't help and it can't really hurt which is a no-loss situation. I have tried it before, interestingly I wanted to push myself a bit harder and try to be better by writing it on online places as well, which meant that when I shared my reasoning and which coins will go up and which ones will go down, that meant that I had a chance to be humiliated by people who saw it, and I could be wrong and they would mock me.
So, I had to really work hard and find correct things not just because it was me making money, it was also about me getting mocked by other people if I am wrong. So at the end of the day I happened to just let it go because it was too much pressure and I wasn't as relax as I wanted to.