This box doesn't have to be just for Magic the Gathering, you can apply the same technique for most trading card games
Sometimes you want it if you have many Unholy Heat and you care about delirium
Green and black are good for self-mill
Due to how this ability is worded, milling several creatures at once only nets its controller one zombie token, so a Sidisi deck benefits from include numerous ways to mill small numbers of cards, as to create a massive zombie army
Adding blue allows us to play one more Nissa planeswalker that works with our gameplan, and Omnath v3s text box goes perfectly with what we want to do: flood the board with Elementals, protect our walkers with those creatures, and then once weve hit enough lands, start drawing a stupid number of cards so we can keep the party going
In the spirit of Azorius, we're going to talk about the best of the best when it comes to blue and white in Commander