It guarantees memory safety without a GC. The result is a high performance language that doesn't require manual memory management like C or C++, and generally consumes less memory, as noted by the Dropbox guys. It's an expressive language which is also suitable for systems programming. It's a more modern language than Go (in the sense that is incorporates modern features, unlike Go which keeps things simple by sticking to familiar features dating back to the 70's), but does require more time to learn.