They each arrive to the battlefield untapped and ready to tap for their color of mana so that you can basically pull a basic land for them easily enough and there is no tempo loss
Theres also decks that care about creature tokens, like Akim, the Soaring Wind, or ones that need a high density of flying creatures, like Kangee, Sky Warden
It shines brightest in artifact-heavy builds with cards like Thought Monitor, giving you both pressure in the air and easy card advantage
Frodo, Sauron's Bane both tempts you and gives you a very good payoff for it
You can do worse
The sequel to Guilds of Ravnica, Ravnica Allegiance continues to raise the stakes for a world on the brink of war, in which the allies of Nicol Bolas are accumulating power as the guilds vie for dominance