I think CSS Modules are onto something. CSS has one huge problem - globals. We have all these CSS guidelines and solutions that have been developed to work around this problem. If you simply remove the problem and default to local scoping per component instead, you have managed to change web development fundamentally. CSS Modules achieve just this.
You can still have global styling, and it can be quite sensible even. But defaulting to local scoping solves the fundamental issue of CSS. In addition, given there isn't a lot of special syntax to learn, you can translate your old skills to the new setup quite easily. This is something other solutions tend to miss as they bring their own abstractions and conventions.
I believe CSS Modules have a bright future ahead of them. The idea is simply too good to ignore. Maybe it's not the silver bullet, but it definitely looks just great for application development in particular.