This isn't particularly surprising
While this helps out most in tossing out Weakness by way of Altaria, there are some other tricks that might just work
Complimenting its massive scale, Emrakul, the Promised End has flying, trample, and protection from instants, allowing it to both easily deal damage and protect itself from instant-based removal
It's missing elements, such as "Energy Cards", that are needed to play the game
Maybe they wanted to avoid paper copies of complicated reconfigure creatures, since those involve a lot of moving pieces already, but the general Magic populace can handle effects like this
But particularly in-demand sets often see booster boxes rocket into the hundreds or even thousands of dollars, as stock becomes more scarce