Some careful deckbuilding is needed, but tutoring for a one-drop creature, enchantment or artifact is an incredibly flexible ability, and can generally find the perfect silver bullet so long as you include it
Sure, 10 mana is a lot to be paying outside of EDH, but 10 mana for 20 power will always be worth it, especially when those tokens are knight-type and get the bonuses from the rest of your knight lords
Quick one here, prices for these should be the lowest within the first week of the release
Note that cards with scry or other similar effects will strengthen the Courser, and this is another tool to empower an already-powerful multiplayer deck type
Admittedly, just about anything that involves March of the Multitudes before Chapter 3 hits effectively ends the game
They are often the backbone of many decks