If you already rely on other creature ETB synergy cards such as Rhythm of the Wild or Aura Shards, why not add being able to swing more easily to that package
On EDHREC, Olivia, Opulent Outlaw is listed as appearing in 1,558 out of the 2,902 Ezio decks logged

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This land functions like a Maze of Ith that can tap for mana, though it only interacts with your opponents attacking creatures
Aurelia, the Law Above Aurelia, the Law Above can sometimes draw into a combat trick or removal that exiles, and you just need to send a battalion yourself, or bait another player into attacking
Wedge or shard staples like Violent Ultimatum or Jeskai Revelation can swing games even harder