I mostly agree, but I also think it's worth doing it for the "side benefits" since they can be so huge, even if you can't predict what they may be.

Cutting a long story short, if it wasn't for tirelessly blogging in the early 2000s, I'd not have gotten a book deal which led to me creating a blog which became my main source of income and led to the e-mail newsletter network I now run. Nor would I have luckily became result #2 for a popular route planner and made $2-3k per month in Adsense over 2 years by accident. And.. a lot of things like that. And I barely had any readers, it's just that certain posts hit the spot with people Googling for very specific things.