You have to learn the browser layout model, yes - you need to know what flexbox is, or how padding or transforms or line height works. But Tailwind provides sensible defaults for how those things are applied, which removes a lot of potential for screwups. It also removes most of the potential for badly “architected” CSS, where you accidentally end up with a set of classes that don’t compose together in a predictable fashion. This greatly lowers the cognitive burden, which helps when collaborating with others or even with your past and future self.

I get that it is aesthetically ugly, but if you can stop caring about that then you might find that it’s better on most other dimensions.