Juggling pre-compiled gpu stuff (css classes) exists for a reason.
Scss is like css.
Jss is css + unnecessary abstraction on top of css + unnecessary memory and cpu cycles + writing part of css rules inside flow control (which can turn into js in css in js.
GPU facing languages have always been ugly and not just in this industry. But they are like that because of their nature. Making them friendlier is always welcome, but replacing them with cpu stuff defeats the whole purpose of a gpu.