Yes I do, less now. I started about 4 years ago. For people who suffer with mental health I can imagine it works as whenever I write things down it helps me not to keep dwelling on my thoughts or feelings.
I've been keeping a journal since elementary. I've lost a lot but still have some from 2010. It's very therapeutic. I can say everything I feel no filter and it makes me feel heard. Also helps me understand what I'm feeling and why. If a situation that upsets me happens it's definitely going into my journal, I also write poetry as well in them.
I started in 99 by tracking my bicycle rides; distance, time, weather and temperature. Then I started adding daily events of significance followed that up with mood feelings etc. It came in handy when trying to put a medical history together and helped with my PTSD diagnosis. So I can vouch for the mental health aspect.
in general it's a good thing, as long as the act of self talk doesn't become an crutch and echo chamber. I know someone who has fallen into the latter, it's meant to be an exercise in reflection, not walling off from reality