So, for someone who couldn’t care less about UI but focuses on UX all the time; does this help me? It looks like the same awful as everything else frontend to me. Why is it interesting? Honest question?
There are so many UX pitfalls that I prefer to delegate the task of fixing them to a library, while still retaining control over how I want to style them.
It's a set of unstyled components components for common UI patterns, with accessibility, internationalization, interactions, and behavior built in, allowing you to focus on your unique design and styling rather than re-building these challenging aspects.
If you don't like doing UI/styling, this probably isn't for you as these components require you to style them yourself.
I've never used this particular library, but if it's does what it says on the box it should make it easier to have accessible components out of the box so the developer is only focused on making it look good.