Silent Fist Kata is just a "fun" spell / distraction. It has no purpose other then to "look cool".
Tiger Form is the same thing, just that you get to shapeshift into a Tiger.
At level 50 you get a nice combat buff. I got it 2nd to last day of beta from one of the dev's because it wasn't put on the vendors by accident. I think it was called Focused Kei or something of that nature. It made a glowing effect that stayed around the Monk's body and upped combat skills.