The problem I have with blogging is the opportunity cost. While blogging may help me as a coder. Does it help more than me actually writing code, or commenting my existing code, or reading an article, or a paper, or spending time reading other peoples code?

I suspect more than anything blogging helps you become a better blogger, and then there are some minor secondary effects. I'm not convinced that if I have zero readers that blogging is the best use of my time.