So zero chance to convince somebody stronger in a certain skill?
If somebody with 10 strength intimidates and you try to reason with your 9 intelligence, you just lose 100% of the time?
RPS is fast, a little fun, and gets the job done. Besides, against the computer you can win 100% of time if you pay attention. Their moves do not appear to be random. ;-)
RPS might make sense for playing with a friend, not for use on NPCs though or in a single player game.
