Even in the best-case scenario where an opponent immediately kills Thalia, she's already cost them one mana more than they built their deck to spend, and likely delayed their curve by a turn
According to many discussions within the collecting community, it's common to lose 60% or more of the money you spend on packs
Yes, the card could have been an instant, and it undoubtedly would have been better
Steel Apron (Wisdom of Sea and Sky) is not available in Rare Packs
However, I think Josu will shine brighter in an archetype that isn't Zombie Tribal at all
Due to this balancing, gameplay in both competitive formats and casual play has become more inclusive of strategies that prioritize a duality of speed and power, as opposed to one or the other