The basic tension here is designers are often not really designing a "style sheet" (even if they think they are). So a lot of elements end up being similar, but not the same. And all responsive states are often 'you figure it out'. Plus marketing involves one-off pages where nobody is thinking about reusability. I haven't used tailwind yet, but the utility-first idea has been around for a long while.
They provide a balance of governance and flexibility that allows team members to work independently to create new designs, but not have CSS specificity get out of hand.
One main benefit is to constrain the actual power of CSS specificity.
The other main benefit is that these micro-styles map closely to design semantics, not functional semantics. This is covered in the OP. At a certain scale, the number of distinct functional semantics grows huge, but the design semantics remain bounded.
