Six mana to get out, and then you have to get 10 counters on him to actually hand out double strike
You lose out on indestructible, trading it for a +1/+1 counter and hexproof until end of turn
With the second lore counter, it either returns an artifact from the graveyard to hand or draws a card
On attack, it forces an opponent to sacrifice a creature, and if they do, you get a 2/2 Zombie token for your trouble
Blood Token Blood Tokens , generated by various means, can fine-tune your hand by transforming unwanted cards into new draws, or allowing you to toss things to your graveyard for later use
As long as you have access to 5 mana, the mere threat of activation makes it very annoying for your opponent to get into combat with your creatures, especially when Dual-Sun Adepts also has double strike