Running Out of Steam? Or Just Bored?

I have stuff I could write about today, but I've started wondering about this whole blog as diary thing.

Is this really helping me become a better writer?  Yeah, it's giving me a venue in which I can actually rack up the time writing, but is it helping?  Or is it just a platform for me to whine?

Would my time be better spent if I sat at the kitchen table, set the timer for thirty minutes three or four nights a week (or more), and wrote?  Wrote a response to something I read in the paper or online, edited something I wrote previously?

I don't know.  But I feel like this blog isn't so much an outlet as something I do every day, like brush my teeth.  Except I'm not entirely clear what the benefit is. 

So if I don't come back for a few days, it's because I'm either writing offline or analyzing the benefits of blogging.