Ever since I started making websites, there has only been one platform that made sense to me. Not only is it the one platform that most blogs were hosted on but after a while it was the one platform that more or less all sites used. I still love using WordPress and it still makes sense but when I want to make a blog that is just that, a blog, I'm open for new suggestions.
Speed is key
WordPress is actually pretty bad out of the gate. A new, fresh installation of WordPress doesn't perform all that great on either Google Speed Rank or GTMetrix. Having good performance is one of the deciding factors when Google determine where to place your website in a search query.
There's many things that will make WordPress do great at these tests or even perform great but it takes a lot of work. Ghost just works. This blog did a 97% and a 92% on GTMetrix with no adjustment what-so-ever.
Either blog or everything
If you want to blog and only need blogging, go for Ghost. If you want make a website for a company, somewhere to sell wares, a community or any website that needs any functionality other than blog posting you'd want to go for WordPress.
Wordpress is great and it have so many great plugins that can make it do absolutely anything. All available through the WordPress dashboard. In Ghost, you can get get comments if you're technically gifted.
I guess the takeaway is that if you just want a blog, why not go for a fast, lightweight alternative to WordPress. If you host your Ghost installation on Digitalocean, it will go lightning fast.