Since Green Sun's Zenith got banned in Modern, players have been frantically looking for a decent alternative. And here it finally arrived in War of the Spark.
It does cost one more green mana, but the effect also allows you to search your graveyard and your library, which means that you can put two creatures on the battlefield.
This card will surely find its way into the Elves decks in Modern and some Stompy lists as well. So the $10 price is fully justifiable.
Currently, Green Sun's Zenith is similarly priced, so Finale of Devastation probably won't go any higher either.