There's blogger, and wordpress(.com), and a lot more, but I (and presumably you and OP) would take anything over those types of platforms.
This fills the gap between 'do your own thing' and 'just use wordpress'.
No matter what you do, GH pages requires more complexity and setup. And that's not a bad thing in this case, it gives you flexibility, but I can see a lot of people preferring prose.sh simply because they don't care about making a website, they just want a blog.
Out of curiosity, was this developed as an exercise in procrastination while preparing for a pharmacology exam?
(I don’t think key creation throws off adoption by developers, who are clearly the target audience. I just didn’t understand which subset of developers was being targeted.)