Then why not just type that, instead of having to learn a completely separate set of concepts to map to the underlying CSS properties & values? I program with inline CSS styles all the time when I'm prototyping something or building a page quickly.

Because inline styles aren’t flexible enough to be used for everything, so you need to go out to external css eventually.

With tailwind you can do “block md:flex hover:font-bold” and you’ve covered pseudo class cases and media queries very succinctly.

It's much more concise than inline styles, variants and configuration give you a lot more power, and it's not a separate set of concepts. It's a subset of the same set of concepts.

See https://news.ycombinator.com/item?id=29502652

It's like radio presets instead of the full dial. Dial is still available, but a great majority of the time you use the presets.