Available Languages. Presumably other languages will be available in the near future. This allows travelers or readers to simply hold their phone up, like a lens, and read translated words.
Effectiveness. The program is in its infancy now, but presumably will become more sophisticated over time.
Cost. One would presume that technology like this would have sold 10 years ago to the Pentagon for a million dollars. Today you can purchase the paid version for about $5.
Video. Below is a video demonstrating the program in operation.