Also agree with @MadsKristensen. All the projects I was working on so far you just want to bundle & minify as easy & quickly as possible and go. The new approach is much faster. Tried to play with gulp and finished questioning myself: "well it is interesting what you can do with gulp but all I only need is right click on css file and minify, or select a few css files and bundle them". I simply don't need to carry hundreds of files and play configuration game in gulp.
The way it is, just one json file is a clean approach and if you do need gulp/grunt you know what to do :)