Too little security
Sure it could be a great idea to have a keyboard dedicated to gifs but the need for the developer to have full access to whatever you type is too much. Sure the information gathered could be used to help better the app with more relevant gifs. Now people are saying that the keyboard will get everything you have typed in the past, thats not true. The developer will only see what has been typed on the gif keyboard only in the past. Not everything else prior to the initial download.
Bunky61 about
GIF Keyboard