I can understand the usefulness (maybe) of using this to extend an existing Rails application, but for a fully static site, I'm not sure why having to go through Rails is good. Infact it seems bad to me, I would rather have finer control over the actual HTML templates and CSS for building a static site.
The gripe about tailwind is valid, but I couldn’t figure out how Perron does this better. From a cursory look, I didn’t see anything about CSS in the docs. I could have missed it though.