The directory structure in Kretes is organized around your application features, and not by type. This means that artifacts, either client-side or server-side are kept together. In other words, this approach groups together entities (classes, functions) that actually work together. This leads to high modularity of your application and better cohesion.
The Folder-By-Feature approach makes it easier to find files in your application directory. It is especially visible once your project grows - folder-by-feature is a better long-term approach due its scalability.