First, this isn't really anything to do with webpack or css-loader; it's an idea which just happens to be supported by, among other things, css-loader. (Also has a browserify plugin.)
Second, I find this idea to be conceptually very interesting, especially compared to the inline styles people are playing with. It works with the existing CSS tooling, knowledge, frameworks, browser optimisations, etc we already have. There's no real workarounds, edge cases, weird hacks, whatever. It's normal CSS, but scoped to your component, which makes reusing components across a project or between projects MUCH easier.
It's not a magic bullet; you have to be smart still about organising your CSS. But it's really quite clever. I'm using it on a decently large project right now; too soon to tell how it'll work out but it's been good so far.
Second, I find this idea to be conceptually very interesting, especially compared to the inline styles people are playing with. It works with the existing CSS tooling, knowledge, frameworks, browser optimisations, etc we already have. There's no real workarounds, edge cases, weird hacks, whatever. It's normal CSS, but scoped to your component, which makes reusing components across a project or between projects MUCH easier.
It's not a magic bullet; you have to be smart still about organising your CSS. But it's really quite clever. I'm using it on a decently large project right now; too soon to tell how it'll work out but it's been good so far.