I believe scope functions are a killer feature of the language. Being able to chain methods and write compact functions without having to declare variables, it makes so much code act and feel functional and direct. Immutability isn't on your list, it also contributes to the functional feel of the codebase.
Definitely my favorite language currently, and extremely well-suited for server-side, it's certainly not just about Android.
Definitely my favorite language currently, and extremely well-suited for server-side, it's certainly not just about Android.