To me, it looks a lot like TailwindCSS but with fewer constraints. I tend to appreciate Tailwind's constraints, as it makes it easier (for me) to fall into the pit-of-success when trying to design layouts with consistent padding/margins/line-heights/etc.

I think cleaning up the hyperbolic marketing language would go a long way for me in terms of taking it seriously (the entire "Why" section does not actually communicate any real information).