So since the original comment was questioning the necessity of animations in CSS, and JS is essentially using CSS animations for many things, I'd say the answer is yes. It's also a great way for UI designers to use subtle movement to hint at actions/status/next steps/etc without having to execute any JavaScript. When you've got a purely visual task, I'd say involving a general purpose programming tool is the unnecessary part— like using sed or the like vs opening up a repl in Python or whatever.
No - CSS and JavaScript are two ways of defining the same thing, an animation. Safari runs its accelerated animations with CoreAnimation - is CoreAnimation a CSS animation?
