People absolutely do use tailwind as an alternative to understanding CSS. Having seen and worked on projects in tailwind, I feel like that's it's primary purpose.
Go on Twitter and look at the Tailwind community - they see CSS as a doomed, awful language and Tailwind as the thing that makes it pleasant. They're not CSS developers. They're people actively trying to avoid being CSS developers.
Tailwind might be nice, but most projects will require in-depth knowledge about CSS.