I think not, because despite the high quality of the pure CSS result, there's probably a js lib out there that will get the same result for a few hundred extra kilobytes in the bundle. But knowing CSS is still very useful as a skill, it's usually your "moat" that makes it hard for backend devs to do your work while you're on vacation.
They shouldn’t be doing frontend work. I’d argue frontend tooling and paradigms are more complicated than backend now.