YMMV and Everyone is different. What works for one person seldom works for a different one.
I don't think you need to follow the format of having to write it perfectly, I see it more as a tool to clarify thinking but I do understand as I don't have a journal habit and I am not sure if it works for me, it does mentally drain me and if I try to do it at the end of the day, I don't think it's useful because i'm too tired and what i'm writing is nonsense, if i do it earlier, I tend to find i exhaust myself with thinking and thoughts that go into the journal without doing any actual real work. I guess in this sense, i'm partly putting my energy into what a writer would do, which is the problem, since I am not a writer.
But I do feel like I need some place to 'think' and writing is a better way of doing this for me, but it's tricky because it can just lead me to going in circles.