Not only do they help bring up the speed of the deck a little, they also heavily increase the resiliency required to play a purely aggressive creature deck in Modern
The land count restriction made it unusable in many games, though the scry ability means its not completely forgettable in todays Commander meta
This cards in a bit of a weird spot where initially, it feels like the higher power you play this card, the more valuable the payoff might be
And that you can sacrifice Spirits to add a red mana to your mana pool, which means that each noncreature spell you cast gives you the potential to cast even bigger spells next turn, or get to a double-spell turn
Creatures (25) 4 Llanowar Elves 4 Birds of Paradise 4 River Boa 4 Blastoderm 4 Ancient Hydra 2 Rith, the Awakener 3 Jade Leech Lands (24) Spells (11) Sideboard Kiblers Red Zone decks was miles ahead of its time, going even bigger than the Fires of Yavimaya decks that usually housed Blastoderm, thanks to Rith, the Awakener
Zaxara may be a modest 2/3, but it's not meant to be a beater
