For what it's worth, the site has been developed by different people over time, so the choice to use Tailwind was made by someone else early on. The team working on the site now doesn't feel strongly about it either way — it's sometimes annoying but overall using it feels really nice! And I'd probably say the same about other CSS solutions too.
I think we'll keep it for now. Where it really shines IMO is fast prototyping. But yeah, it's cool.
Edit: Ok ok tbh I do like it.
It's taking a long time because there are edge cases to figure out if we don't want the upgrade to be painful for certain sites, notably the ones using anchor links or i18n. It's not far from the end so hopefully mdx2 will be merged soon.
Old but still relevant.