Alright, Alright, just kidding, jeeze...
Straight from Wiki: The cards of this archetype relies on Special Summoning and destroying cards mainly by Tributing other "Hieratic" monsters. What makes this archetype powerful and interesting is that many of its monsters allow you to Tribute from your hand, in a manner similiar to Ritual Summoning.
Another: The greatest strength of this archetype lies in an ability that almost all its members possess: upon being tributed, be it by cost or effect, you are able to summon any normal Dragon type monster from your hand, deck or graveyard, at the cost of its attack and defense being 0. This gives the Hieratic archetype the ability to swarm the field and bring out powerful Xyz monsters in a manner similar to the famous (or infamous) Wind-Up or Inzector archetypes.
Another interesting thing to note is the ease of summoning the archetype's regular members, and the ease of which you may activate their effects. For instance, both Hieratic Dragon of Nebthet and Hieratic Dragon of Su are capable of getting rid of problematic monsters or spells/traps simply by tributing a "Hieratic" monster from your field OR hand. Not only that, but by tributing a "Hieratic" monster, you activate its effect to special summon a normal Dragon type from your hand, deck or graveyard, which means you literally get to destroy your opponent's cards and get a free monster for your troubles.