Whether it comes down on turn 4 or turn 6, you gain a massive advantage when you kill a creature and eventually get a massive threat, especially once you consider that this can go face to remove your opponent
Kakus cost of 5 also prevents it from being sent back to the players hand by the Trafalgar Law card from the Blue Donquixote Doflamingo Starter Deck [ST-17]
The ability to tutor for equipment is already great, and the hurt you can put on with Lost Jitte, Umezawa's Jitte and pretty much any sword is critical
You can track that with a D20, a Life counter, or just write it on your Notes app
The Pokemon TCG has also released their own official Halloween Set of cards called Trick Or Trade
Ultimately, any great archetype needs to offer great first picks that call out to drafters and (ideally) demand support