The one issue I have with Obsidian Publish is it's a bit of a pain to put your own SSL-secured domain in front of it. I run a nginx-based proxy as a bandage. I can see why someone would not want to pay $8/m for it though when there are a ton of free options out there. You have to remember that devs love flexing their skills and automating a blog can be fun, it's not really anything wrong with the service.