For me, what the browser needs it's a good DX to build components, I kind of like Svelte and Vue in that regard, where your CSS, HTML and JS lives all together.

Writing a CSS file with the time will start growing and at some point will be very hard to know what to keep and what to delete, I think this is the reason why tailwind became popular, because it keep only the used rules, now the downside is that now your html elements has ton of classes.