Hmm... Don't take this the wrong way but the point of CSS is that it can be modified by people that are good at, you know, CSS - a class of people that generally does not include your average java / PHP / javascript developer.

I agree entirely with 'scoping styles to components' but css in js is a massive step backwards when this can be accomplished much more simply by maintaining a less / sass / css file in the same folder as the js and importing it.

My two cents, as a contractor who is paid to fix other people's code: there is an aspect to semantic HTML which is the descriptive nature of attribute class names. This is completely destroyed by css-in-js.

In short: I can easily track down the styling (and probably the component) in the code based on an attribute classname. How on earth do I do that when every single class is named some combination of 'R23RG67ED'? I know there are things you can do in Webpack to create some sort of descriptive name ('component_1-wrapper_2-div_3-my_wacky_component_5-GEWRCER anyone?) but a) nobody does this and b) if the only reason we're implementing css-in-js is for issues of scope, surely this is not a step forward?