I like the idea of those preprocessors (and do use them on various sites). But, in practice, I tend to prefer normal CSS. Even on fairly large sites, well-written CSS is (or should be) reasonably manageable. (IMHO).
Also, one thing I find a little annoying about the preprocessing is that, when it’s finally compiled into normal CSS, the line numbers change, making it tougher to just look at the inspector and see what line # the rule is on. I know there are workarounds for that problem, but it’s still annoying to me.
In online forums, I see a lot of shock at awful selectors like that one you mentioned. They’re funny, for sure. But, I suspect they’re there often because a CSS person has been asked to fix something on a site that’s utilizing a CMS, probably an awful theme on top of that, and considerable additional CSS and HTML (or lack thereof) on the page. Sometimes it’s all one can do to cobble together some ginormous selector to fix whatever poorly designed issue is at hand. :-)