The node_modules folder is still somewhere on your system (~/.npm/_npx probably?) containing the same tailwindcss dependency files, but if it helps you sleep easier at night it’s okay to pretend it doesn’t exist.
No kidding, I thought global tools worked with fairy cloud dust, now I wont be able to sleep! But knowing there's not a going to be a bloated node_modules folder and local dependencies running different versions unnecessarily maintained in every project will definitely help.