Next JS + Tailwind Testing

Has anyone tried tailwind in a project before, somehow when I am creating custom value on the 'tailwind.config.js' the default value doesn't work, for example I created 'circle' for height, using 'h-circle' then somehow 'h-full' or 'h-screen' doesn't work, similar thing happen with bg, I did have the purge on the config so I don't know if that's the thing that did it.

Also what actually is the benefit of using tailwind. Yes this project is not meant for using that but when dealing with repetitive styles its kinda annoying to keep making them, well I suppose I could have just used a loop for the data input, but still curious of what people think of tailwind.

Thanks for reading and sorry for rambling