By locking down colorless mana and colored mana sources alike, it can stop your opponents from activating their lands for mana entirely, which practically warps the rules of the game in your favor
It's delicious no matter how it's served
These codes will often reward you with a card style, which is a skin of sorts for specific cards, or artwork for sleeves, so you can make your deck look a bit fancier
4 Thalia's Lieutenant Humans are one of the most popular white creature types, if not the flagship white creature type
He said maybe in the future last time I checked
The key difference is that they lack basic land types (a relevant change for any format with Fetch lands), and that they enter the battlefield tapped unless you control two or more of any other land, not just basic lands, but they are also only be available in allied color pairs