I'm the author of another React static site generator (https://github.com/gatsbyjs/gatsby).

I totally agree that for many sites, using Phenomic or Gatsby would be overkill.

But for something small, it doesn't really matter what tool you use as long as it's familiar. For small projects, familiarity trumps any other concern.

React came out of Facebook that needed a frontend technology that could scale to 1000s of developers.

Gatsby and Phenomic are both an attempt to port the best of the React ecosystem to the world of building web sites. They're designed so that as your website gets larger and you add more people, the code still feels simple and it's still easy to make changes and add new features.

So yes there's a learning curve and some overhead but it really pays off for larger projects.

And the nice thing is that once you understand them, they're now familiar so just as easy to use on small projects as any other solution.