Reason / Believe I have reason to believe (pun intended) that certain decks can cheat big creatures into play using a combination of top-of-library manipulation and Reason / Believes two effects combined
This allows you to play out your turn without having to worry about someone trying to interact with you with removal or counterspells
Cards that create tokens off landfall triggers like Scute Swarm and Springheart Nantuko are essential components of this deck to provide the commander with sacrifice fodder (and enable some nutty turns with Intruder Alarm)
That means the card is also an incredibly powerful Commander option
For example, if it blocks a 12/12 creature with trample, that creature's controller must assign at least 8 of that creature's combat damage to Diamond Weapon, and the remainder can be assigned to the defending player, planeswalker, or battle
Sunstreak Phoenix can alter the day/night cycle and return from the graveyard to the battlefield as days and nights change