Another Jekyll advantage: Jekyll it makes it easy to host a blog under your main domain.com/blog, without the need to use a subdomain, without the need to fiddle with Wordpress and without the need to switch your whole website to a (new) CMS. This is a huge timesaver (We use it at https://a9t9.com/blog and a very happy with it.)
According to the SEO Guru(s), this brings a SEO advantage https://moz.com/community/q/moz-s-official-stance-on-subdoma...