Signily - Communicate with sign language on iOS

Is being able to type in sign language vs typing in any other language preferred by deaf users?

"When it comes to communicating on mobile for Deaf people, sign language isn’t really an option unless using video messages. That’s about to change with the release of Signily, a sign language keyboard app for iOS (coming soon to Android). The keyboard uses emoji-style hands portraying accurate signs and shapes." More on TNW: http://thenextweb.com/apps/2015/...