Gatsby is an SSG built around React which provides amazing set of tools and environment for generating blazing fast webpages. When we talk about speed optimization, nothing can really beat static HTML files.
Developer experience is another great advantage, React developers will feel right at home from the start.
Is there really any single reason not to build blogs like this one with Gatsby? I don't think so :) But don't take my word for it, go ahead and try it yourself!