Good things. It does bring customers directly. At least for blogging, building in public posts can get some backlinks, which is great for SEO. For some time I had the #1 result for my top search term. That might make it worth it overall.
Negative things. It motivates others to clone your project, as now people know that $X/month can be made doing that. Almost no-one will, but if your posts are seen by say 100k+ people then you'll have a few in there who might.
It warps your own thinking, as now you have a bunch of people on social media who see your project as your identity. You start buying into the narrative of being this X project guy so you can't just go away to do Y, even if on a rational level you know no-one actually cares that much whether you do X or Y.
Seems @levelsio has been immune to this, as he's been smart to have his identity be a guy who ships a variety of things quickly vs. just being say the "Nomadlist Guy" forever.