There are two possible reasons (probably more) that the pen may actually be helping your handwriting here:
You're probably putting less pressure onto the page, which means that you're not fighting against that friction every time you need to change direction.
Your pen seems to lay down a pretty thick line - that's something that can often make the imperfections in one's handwriting less visible. (That's not intended as a dig at your handwriting, in fact it can be a useful thing to keep in mind if you're writing something like a birthday card where you get one shot at making it look good).