It works in some cases as a pattern of keeping components very modular and only loading the styles on the page that a single component needs. And I think it works well in cases where a component is very unique and wouldn't share any styles with other components.

That said, I personally see it as an anti-pattern. Styles should be kept agnostic of application logic for the most part. Practicing proper BEM convention paired with proper organization of SASS files yields simple management of style logic. This works exceptionally well in complex applications.

There are two camps forming right now with different methodologies & use-cases in each, and it will be interesting to see which patterns are implemented & what kind of 'css in js' tools become available.