It forced me to learn Amazon EC2. I wanted an excuse to learn how to use it for years, but never did. Thanks to this excellent tutorial and some searching, I now know how to setup and maintain an EC2 instance with associated services. It's good tool to add to the toolbelt.
Ghost is Simple
There are few settings to wade through and extensions to configure. Instead of wasting your time worrying about all of that, you can get straight to writing. There is some manual configuration (e.g. adding Disqus comments took some vi), but it means you have to know what's going on with your blog. It's like a PhD student analyzing his or her own data instead of outsourcing the statistics. It is a good way to approach blogging.
Themes are Elegant
The themes I have looked at have all been elegent. This includes the code. The platform was designed to look nice. Most blogging platforms make this difficult, Ghost does not.
If you haven't looked at Ghost yet, give it a whirl. They have a hosted option now, which can reduce the learning curve, but take away some of the fun. More themes are coming online all the time and the community appears to be growing.