You're right. Don't use Tailwind if you don't know CSS well.
The use case is for creating Template Components with something like React, Vue, Hugo, Razor or another component template framework. Tailwind offers a large list of customizable variables to use to help keep your CSS consistent. You're still pretty much writing CSS though, just with shortcuts. I consider it Emmet CSS + Variables. I also highly suggest using a plugin for your editor that offers hinting on all the crazy names no matter what CSS framework you use.
If you want a higher abstraction, Bootstrap or Foundation provide that. There is now also this Tailwind UI that you can purchase that would also provide that to some degree.