> You don't need CSS to offer an additional unit of reuse

Erm. Isn't this one of tailwind's selling points? That you have a set of classes that you keep reusing?

This is technically true, but misses the point. Tailwind classes are fine grained utility classes, the fact that they are CSS classes at all is pretty much an implementation detail.

Compare tailwind classes to bootstrap classes and you'll see what I mean.