Because they take a while to get going, theyre often vulnerable in the early game, especially if they dont have any other attackers
Being able to take a defensive stance and draw games out accomplishes much of the same thing but is sometimes difficult to accomplish (especially nowadays) and can be risky if the opponent has a bomb or game breaker of their own in their deck
Also, we get to see Quina taking a bite of a monster
If the card Radagast, Wizard of Wilds is anything to go by, this deck might also have a more generic Wilds-matter theme, with it caring about both Beasts and Birds
The other Gearhulk cards are also pretty valuable out of the gate: Riptide Gearhulk and Oildeep Gearhulk are also in the $9-$10 range
Your opponents copy will always resolve first, so keep that in mind when negotiating who you want to target