[PvK]

If assassins were always an effective efficient attack, it'd be a bit silly. Assassins are good for surprise and keeping people off balance, and/or getting them to over-compensate. Many Dom players are highly paranoid and get overly upset when anything goes against their plans, so they tend to overreact to assassins. Assassin attacks at a ripe unexpected moment can be very worthwhile, especially if they get someone important, or take out a commander moving troops into battle.