> For example, several of the next.js examples[1] use tailwind without explicitly stating so, because I guess it's just become a ubiquitous as css stylesheets or modules for some people

I used Bootstrap for years and give MDO major props. I learned Tailwindcss actually because it was starting to show up everywhere and many of the Next.js examples were using it. Now that I have used it I would say it changes how you think about css and styling - it gives you more power and more guardrails and it also then ships a smaller css load to the client. It was always a struggle to carve away the parts of Bootstrap you weren't using.