I don't journal daily because I don't have enough to say every day, but I do something similar called "writing therapy", especially when I'm feeling emotionally stuck. I find bad emotions to only be bothersome because they are inside and unprocessed. Externalizing emotions onto a physical page (not digital!) helps me process them. The physical act of subsequently crumpling the piece of paper and throwing it out is catharsis. The act itself somehow tells my brain not to hold on to certain feelings -- I've done the work to process them and I can now let them go.
I do this when I'm experiencing minor issues that don't rise to the level of needing to talk to a $150/hr therapist. Some people prefer talking things out, but I prefer writing.
"So what do therapy, journaling, and meditation all have in common?
All three are techniques to help us convert what is usually the subject of our consciousness into the object of our consciousness.
That’s it." [1]