Fake.
The app gives access to 1 or 2 emojis that are not yet present on the system keyboard. The standard emojis are at the more confusing order so that someone could think there are more ones that he haven't seen on system keyboard. The additional pack contains those icons that don't exist on system font so that they can't work. But you should pay to find this out, all of them are locked. I guess that it inserts images into iMessages text to fake emojis, so this can't work in all places where text can be typed.