Honestly, I never understood the move to create an artificial dichotomy between design and code with a heavy layer of tooling.
I suppose that a layout engine made sense in the context of Flash, and you saw the future of the web as a set of keyframe animations. But the notion that there's a lot of value in creating a very heavy, high-friction abstraction between the UI/UX and the platform it ultimately runs on was always going to be a loser.
In the end, it turns out we're all just web developers, regardless of your weapon of choice.