Excerpt from here: https://magic.wizards.com/en/articles/archive/feature/creating-global-series-jiang-yanggu-mu-yanling-2018-06-07

However, one very, very important element to us was not to fracture the competitive scene. Having Chinese Standard and European or North American Standard look very different would not be good for the game, because it creates discordant information and doesn't allow information and decklists from one place to transfer over to the other. And that's not even factoring in pieces like Magic Online!

So, Play Design was very careful to make sure that the cards were balanced so that none of them were cards for Constructed. We're always careful with Planeswalker Decks, but especially here we wanted to be even more careful than normal.

After all, the most important aspect of these decks is that they teach you how to play. And if it's clear that cards you get in your booster packs are often stronger than these cards, that's actually okay: it's a great pathway to upgrade your deck when you're new.