> I've been wondering what is the benefit of putting up your own web server or scripts to serve your static content when you could put it in a Github repo or serve from something like S3?

I think you're overestimating the work required to put together a web server. For example, you mention dumping files in a S3 bucket, but that doesn't require much more work than whipping out a nginx instance and dropping said files in a folder.

Also, some people already run their own servers or deploy their services in some cloud procider. The work required to put together a blog is minimal.