A bow is designed to apply pressure from long range, forcing its victims to take cover. This allows the bow user to freely advance unless he's against another bow user. It's a bonus if a user deals decent damage on OP mode using the bow. The more proficient the shooter is, the more pressure he can apply.
Unlike swords, using a bow efficiently depends on how well the user can aim (of all the PvP weapons in the game, the bow has the steepest learning curve). A bow user who lands only 10% of his shots will burn though a lot of ammo with only a very few hits. A better user with the same bow who lands at least 50% of his shots will still have ammo to spare, all while leaving you crippled. An even better user will respond to what you're doing with a variety of arrows and tactics, shooting nastier arrows only when he's confident that he can land the shot and follow up immediately after.
At longer range, it becomes much harder to land a precise shot, but it's not unheard of to land shots from mid all the way to a starting island. Building high (the higher you build the better) also makes it harder for the shooter to land shots as bow shots have a maximum height AND the hit will not knock you back as much since the hit would be angled more from beneath than from a side.
Kenobi was a very good user of the high ground.
