It breaks readability of your site without JS. That’s particularly bad for the “old” (mlmym) UI which would otherwise be usable for basic interaction without JS entirely, but I find it annoying every time I end up loading a page from lemmy.world directly – e.g. to check federation.

That’s one of the reasons why I’m on reddthat instead of lemmy.world: old.reddthat.com works without JS.