Taken literally, Obeka wouldnt bypass Soulshrieks sacrifice if played as it reads on the card, but in the current rules absolutely does.
Allies have been around since 2009s Zendikar, and frequently interact with other Allies
And they can provide a final wincon
The third in a series of MTG Secret Lairs tied to the character, while the Spring drop was full of cherry blossoms, and the Summer drop celebrated the power of music, in Hatsune Miku's Fall Secret Lair she's playing dress up, alongside her vocaloid pals
Iconic cards are even rarer than Enchanted
Not only does it help you enact your game plan of kill everyone faster, but it helps avoid situation where the player you chose to kill last ends up popping off and winning in the very end