Ok, since I suggested the thread, here's an idea for a developer:
Make a Morse Code app. The taptic device can tap out the code for the letters selected and force touch can then send the message to a friend. By tapping and holding you can do Dashes and Dots. Visually you can then SEE the letters as you tap them.
A learning mode would allow you to see the letter and the sequence and tapping it properly awards a prize or the letter changes color or something.
I could see it as a way of learning Morse code AND of being able to send/receive messages with those on your friends list without ever having to look at the watch interface.
Think of the espionage fun that could be had.