Maybe I did not understand how to use it, but it does not seem to be a keyboard option that you can install and access from your keyboard while texting (as the emoji option is): its just a pad where you write in your chosen font and then copy and paste into the app youre using - iMessage, whatsapp, etc. It does work but its too much of a workaround for me.
Verdemilo about Font Keyboard Free - New Text Styles & Emoji Art Font For Texting, v2.0.3