Hi there !
There's absolutely no need of server compute when it comes to personal blog or so. Ghost looks like a nice alternative to Wordpress, however I think you should definitely take a look at static site generators such as Hugo, Jekyll and alike.
What you win :
performance (you can't beat static files directly delivered to your browser when you're free from the hassle of server side compute, + it's pretty simple to add a CDN layer on top of that and since you're all static...well...everything can be cached ?).
security : again, no database and no server side code at all...
less costly : You can host static website on solutions such as AWS S3 (Azure also has its own blob stuff to do that) and it's really cheap as it's only storage that you pay (and bandwidth, but you'd have to drive some crazy trafic to start feeling it costly - knowing that you can delegate that bandwidth to the edge CDN instead of your origin servers or buckets, it's definitely a win situation).
Some demo example : a quick blog I built using Hugo to test the S3 website storage :
http://loneworg.com/ (total cost : $1.3 / month, and how fast was it when it loaded ? Note : it's a bucket hosted in Ireland - but I could distribute it to other regions as well)
And static does not mean your site will not be dynamic (just means that everything is client-side). You can have comments integrated through third-party plugins like Disqus on my demo above. Feel a difference with wordpress ?
So where's the catch ?
What you lose :
The back-end and WYSIWYG. Most of these static gen use markdown for post editing. It's a bit tedious if you're not use to it. However you may find some options here and there that will offer you an easier way for editing (like with the netlify cms for instance, or forestry.io from what I remeber ).
Much less themes/template choices for now. Gallery for Jekyll is ok and Hugo / Hexo ones are growing as well, but you won't have the incredible plethora of templates you may find with Wordpress : meaning probably more HTML/CSS customization needed from you.