Maybe cause having a high number of observes to give you extra attacks in combat, or a semi-random prog in battle that does a good amount of damage, like prayer beads or Maran weapons but with an arrow, only on the person you've been observing.

Also, cause high observes to lower the lag of aimed shot from two rounds to one. Makes sense you should be able to predict where they're going to be if you have been watching them for so long.