Doing anything chess-related for a long time will probably result in some imrpovement. However, I believe bullet chess is one of the least effective ways, bringing the least improvement for a unit of time. Blitz helps in pattern recognition, but not much else, as it's very "shallow chess".
On the other hand, chess is about having fun for the most of us. I don't play blitz because the stress makes me frustrated, I do things I enjoy (annotated games, tactics, long games) instead. But if blitz makes one happy, playing blitz is the way to go.
I sort of agree. But in the long run, playing lotz of Blitz game will eventually make you improve (if you're thinking right at least).