I think it will mostly see play in decks aimed more at the moderate competition level, not at the highest level of competition, where there are decks with capabilities to easily dish out damage that dont rely on a character questing
It doesnt make a huge difference in 2-color decks, but 3+ color decks love this for its low cost and easy fixing
This is largely down to how hard it is to deal with early walkers
After sacrificing Zack and sending him to your graveyard instead of your command zone, reanimation effects like the one on Sun Titan can bring him back into play or to your hand to restart the gameplay loop , allowing you to keep stacking counters on your creatures
By making them both uncommons that green-black was happy to play, the cost to put them in your deck was low enough that you'd take them both, and then it's time to Ragnarok and roll
Its particularly potent when cheated out via reanimation effects, too, or cards like Sneak Attack